Ion selective electrodes - ACS Publications - American Chemical Society

ANALYTICAL CHEMISTRY, VOL. 50, NO. 5, APRIL 1978

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Ion Selective Electrodes Richard P. Buck The William Rand Kenan, Jr., Laboratories of Chemistry, The University of North Carolina, Chapel Hill, North Carolina 27514

HISTORY, NOMENCLATURE, STANDARDS, REVIEWS, AND BOOKS Ion Selective Electrodes (ISEs) are used by scientists in all nations. Illustrative of this wide application are: a review (293)and two preparations of solid state electrodes (403, 433) from three areas of the Peoples Republic of China; determination of fluoride in North Vietnam using an Orion 94-09A electrode (399);a series of four papers on silver halide membrane electrodes from North Korea (228 221) and South Korea (238). T h e extensive review articles begin with Sollner‘s (375) history of membrane electrochemistry, covering the period mainly prior t o 1930. T h e internationally known institute directed by Nikolskii (Nicolsky) at the Leningrad State University has developed many pioneering aspects (glass, solid, and liquid ion-exchange membrane systems) of this field. History of ionometry (301),current status of their research (302),their views on membrane selectivity (267)and use of ISEs in soil-agriculture (235)were published. The references in Ionnyz Obmen Ionometrzya serve to introduce a new journal “Ion Exchange and Ionometry” edited by Nicolsky. Terms and symbols for use in papers on ISEs were established by the IUPAC Committee (191). The symbol kyk is thus sanctioned to designate the potentiometric selectivity coefficient. However equations and methods for establishing selectivity coefficients, while defined, may be subject to revision. collections of selectivity coefficient data are badly needed. An obscure paper on selectivity coefficients for ISEs has been published in Japanese (308). Of course, many selectivity coefficients are already accumulated in books. Ion activity standards for pH and for ion activity determinations with ISEs, as developed a t the National Bureau of Standards, were described by Durst and Bates (102). Closely related were response studies of Na+, K+, Ca2+,H+, and C1- in buffered. serum-like (0.16 M ) media using junction and junctionless cells, including an LaF3 reference electrode. Responses were near-Nernstian t o ionic concentrations (281). Major reviews on practice and theory of IS&, and new books are by Bailey (17),Baiulescu and Cosofret (18), Bloch and Lobe1 (37),Buck (44, 45), Koryta (232),and Lakshniinarayanaiah (239,240). Ms. Pick prepared a list of 450 major references (323). Recent developments were compiled also by Simon e t al. (373). More specialized reviews include ion-exchange membranes by an expert on desalination (333), membrane potentials in thermodynamic context (32)and in the context of seawater speciation problems (423),pharmacy (French, 406), general reviews in Spanish (325-327),and a good description of standard and analate addition methods by Mussini (Ital. 292). Further reviews by specialists include Freiser on coated wires (223),Tenygl on applications (389), Thomas on anion analyses ( 3 9 I ) , and Durst on general properties of ISEs (100). T h e simplest form of bioelectrode. i.e. Ag/AgCl/fixed C1 , used to measure ordinary Galvani potential differences between inside and outside of cells or across synthetic membranes is reviewed by Rottenberg (345). Unfortunately Matsuo’s review (270)which covers his work on CSSDs (see below) is in Japanese. Other applications of ISEs in biological environments or systems are reviewed by Durst (99) and Thomas and Moody (282, 392). Reviews aimed a t enzymologists and clinical chemists have also appeared (283,377). Fuchs has prepared a short book on ISEs in medicine (126). In addition to t h e NBS Special Publication (2961, t h e proceedings of t h e Schloss Reisensburg Conference on Ion Selective Electrodes in Biology and Medicine (215) and t h e proceedings of the October 1976 Matrafured Conference on Ion Selective Electrodes (332) were published. Both are in English and contain many important papers. 0003-2700/78/0350-017R$Oi .OO/O

Applied analysis using ISEs in specific fields include agriculture (284),tobacco and smoke (289),flue gases, waste water, and pollution control (56, 248, 328, 330, 398), paper industry (86),metal finishing (428)and oceanography (327).

FLUORIDE SENSING ELECTRODES Once again, an effort has been made to connect, reversibly, ionic with electronic conductors. Lyalin and Turaeva report that LaF,, bonded to Ag behaves reversibly (255, 404). However, their subsequent paper uses conventional filling solution for the LaF3 membrane (256)! A patent was issued for the Radelkis LaF3 electrode (92). Further examples of mixed aqueous-organic solvents for fluoride determinations which decrease the detection limit to 2 x lo-‘ M, were offered (387). T h e suggestion has been made that Tiron is effective for A1 masking (388). Response times of LaF, electrodes are complicated by microcracks and possibly by surface films. I t is our experience that single time constant responses by perturbation methods only occur using fresh electrodes and that polishing and thermal shock lead to microcracking and superposition of simple time-dependent responses. Very careful and thorough studies by Mertens, Van der Winkel, and Massart (273,421) have characterized and correlated step activity responses and impedance responses. Many applications of F- determinations in inorganic materials have appeared in Russian and Polish journals. Generally the methods are already well-known, involve fusions (no distillation), and use buffers fortified with complex formers such as citrate. Similar, but rather well-known methods have been published for F~determinations in soils, in waste waters and in nonferrous metals. Round-robin analyses (23 laboratories) have been used t o establish validity of F- determination in vegetation, foliage, and soils (195,410). Similarly F determination in urine (295) and in blood (374) have convinced many to avoid the Willard--Winter method. Determination of F- in seawater by direct potentiometry has been reported by Russians (233). However, Rex, Bond, and Smith (342) use standard additions to avoid use of buffers or calibration curves. Both F- and Na+ selective electrodes have been used to study the continuous aqueous phase compositions of microemulsions (257).

GLASS ELECTRODES I N MEMBRANE CONFIGURATION RESPONSIVE TO MONOVALENT CATION ACTIVITIES Isard (290) has outlined the simplest view of glass electrode responses, in which he accounts for steady-state responses according to normal ion-exchange theory, and for long transient responses by penetration of ions through a hydrated layer. Existence of regions of varying site density, varying cation concentration profiles, and spacially variable cation mobilities are accounted for, but effects from these sources on potentials in the pure pH-responsive range aren’t apparent. Bailey has also reviewed glass electrodes (26). Detailed analysis of cation concentration profiles from surface to bulk with resolution of a few tens of angstroms, using ion-beam induced radiation, has been pursued by Bach and Baucke (15, 29, ,301. Despite the nonequilibrium character of the leached, hydrated layer and the formation of a high-resistance layer (between leached region and underlying intact glass), Baucke advocates an ion-exchange surface (interfacial potentialdetermining) process involving SiOH groups (26). A further analysis of the differential membrane potential equation for glass membranes was given (370). A closely related paper in English will appear in the Proceedings of the World Congress on ISEs (Budapest, September 1977). Another fundamental problem in glass electrode behavior is the potential overshoot after sudden changes in bathing solution cation composition. C 1978 American Chemical Society

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Table I. Glass Electrode Technology 1. 2.

3. 4.

5. 6.

7.

8. 1. 2. 3. 4. 5.

Conventional Formats Demountable combination pH electrode with built-in thermistor. All-solid-state glass electrode configuration bulb with fused ionic conductor inside. Sodium ion-selective composition with A1,0, and Ta, 0 , . NaJ-alumina as basis for Na+-selectiveelectrode. Comparison of Na' analysis in foods by AA and ISEs. Determination of Na' in alumina. Comparison of K' analyses by four different and unusual electrodes: minerals in supports, K-selective glass particles in paraffin, KBPh, or K dipicrylamine, etc. in paraffin and an oxidized carbon rod. The latter was preferred for monitoring titrations of K' with BPh,-. NH,'-responsive glass compositions based on sodium-aluminosilicates (and vanadates). Micro and Medical Applications Microelectrodes for pH (spear, internal capillary, and recessed t i p ) . Microbulb pH electrodes. Elongated tube combination pH electrode suitable for catheter applications. Flat pH-sensitive electrode for skin and other use. Tip potentials and resistances of microelectrodes.

The overshoot phenomenon occurs for electrodes with surface films (hydrated,leach-layers). Rapid ion exchange-adsorption of a favored ion occurs at the electrolyte/leach-layer interface. Later, diffusion of all counterions through the leach-layer, toward t h e intact-glass interface produces compensating diffusion and second interface potential components (at the leach-layer/glass boundary), and drives the potential back toward the proper, predicted steady-state value. Analysis of this effect is based on prior studies of temperature and stirring-dependence of rising and falling potential excursions. A new study ( 2 )compares these transients for commercially available (Orion and Corning) p H and cation glass electrodes. Another in the long and elegant series of papers on glass electrodes from Umea (206),describes the long-term drifts created when electrodes are alternated from etchant to non-etchant electrolytes, acid-to-base, and strong-to-weak buffer solutions. Time-dependent potentials after acidicfluoride etching have been studied (40). So-called "acid" errors (really anion-penetration errors) have been carefully and extensively documented (68,271),and analyzed in terms of Donnan-exclusion failure using the Eisenman nonideality hypothesis (46). Acid errors correlate with molecular size, Le., less pronounced for larger acids. Lesourd et al. (243) have used the nonideal hypothesis for interpreting potentials of Pyrex glass membranes surrounded by molten (Na, Li)NO,. Selected papers on glass electrode applications, glass compositions, and microelectrode constructions are compiled in Table I. More unusual designs involving glass-to-metal seals and contacts and p H glass-to-insulator contacts have been slowly developed over the last decade. I have commented on these before, as examples of systems with predominantly capacitive contact between regions of ionic conductivity and those with electronic conductivity. They are receiving attention as component phases in CSSDs (chemically sensitive semiconductor devices). Dobson (90) has patented and claimed a H+ or Na+ sensitive device from a mixture of glass or mineral particles in an epoxy or silicone matrix, either with metallic contacts or a metallic backing. Another patent claims sodium-bronze and Nai3-alumina in contact with Na-Hg-Pt (91). Related to the former is an electrode structure in which ion-sensitive glass is bonded to a metal backing and contact (112). Still another patent suggests a structure of glass on metal on insulating substrate (384). A new study of the impedance-frequency responses of Pt/glass and Au/glass finds t h e expected parallel RC equivalent circuit (335).

SOLID ELECTRODES FOR BOTH ANION AND CATION ANALYSES The number of new materials and new concepts in this field is relatively small. Perhaps nature has not provided common materials with suitable ionic permselectivity, and the efforts t o create materials with ideal properties may be a fruitless task. Some new formats and materials are offered in Table 11, P a r t A, while applications are in Part B. More commonly known applications or minor improvements are not included because the basic ideas and comparable procedures are found in books.

Certainly, interpretation of solid electrode potentiometric responses has lost its interest to some analytical and physical chemists. Nevertheless, much better understanding of solid ISEs is possible, and progress is being made. Identification of the processes at work was accomplished little more than a decade ago, and important applications of these principles are still occurring. The main topics which have been treated recently include the factors determining lowest level activity responses in pure systems, role of interferences in terminating low level responses, role of complexing agents in determining responses of cations, nature of selectivity coefficients and the interplay between nonequilibrium corrosive attack on electrodes and thermodynamic (equilibrium) conversion, origin of time-dependent potential responses, and the problem of ionic/electronic conductor contacts. Midgley (279) has given mathematical procedures for analyzing low activity, non-Nernstian solid-electrode responses to diagnose (1)presence of responsive species in reagents, (2) presence of interfering species in samples, and (3) nonequilibrium between electrode material and solution (lack of presaturation of sample with electrode materials). In two papers, Liteanu, Hopirtean, and Popescu (250,251)establish a statistical basis for the linear domain (Nernstian or at least linear in log activity) and the low activity level (curved response). The detection limit has a definition in terms of the extreme low value of the linear domain. Hulanicki and Lewenstam (185, 186) have used the steady-state (nonequilibrium) diffusion-controlled theory of surface attack to interpret interferences on solid-state electrodes via the usual metathetic reactions. At low activities of interference (e.g., Br-) in a solution adjacent to AgC1, the thermodynamic driving force is not sufficient to completely convert the AgCl to AgBr. Consequently the classical theory, an equilibrium theory, which describes the potential response to interferences in terms of the ratio of solubility products for unit activity solids, will not generally apply although certainly equilibrium interference responses conform to this model. In the nonequilibrium condition, potentials are still determined by surface activities of reversibly-exchanged ions, b u t these activities are determined by the flux balance equations. The authors treat a wide range of cases (in terms of the equilibrium constant for corrosion) and find selectivity coefficients, given by simple ratio functions of aqueous diffusion coefficients, to be obeyed experimentally. This view, which attributes the major effects just below saturation to diffusion control, does not account for any activity variations of the deposited solid-interference salt. Other workers find the same effects, but explain them in terms of different forms of deposit (AgI on AgCl (227)). Another group compared measured equilibrium selectivity coefficients for membrane AgX and 2nd kind electrodes AgJAgX, and found them to be the same, as expected (156). T h e question of time response origins for membrane electrode potentials after abrupt activity steps, or after current steps remains mildly controversial. For parallel-face homogeneous permselective membranes with permeant species whose motion obeys Nernst-Planck equations with constant

ANALYTICAL CHEMISTRY, VOL. 50, NO. 5. APRIL 1978 Richard P. Buck received his B.S. and M.S degrees in chemistry from the California Institute of Technoiogy in 1950 and 1951. respectively, and his Ph.D. in chemistry from the Massachusetts Institute of Technology in 1954. Since then he has been assistant research chemist, California Research Corp., 1954-57; research chemist, California Research Corp . 1957-61; principal research chemist, Bell & Howell Research Center, 1961-65; senior scientist, Beckman Instruments, 1965-67; professor of Chemistry, University of North Carolina and assistant director of Crystal Growth and Analysis Laboratory, 1967 to the present. His work includes many facets of electrochemistry. Among these are theory and practice of electrode process identification and measurement, coulometric methods for batch and continuous analysis. and construction of ton-selective electrodes and crystal membrane interface and transport studies. He is also currently working in spark source mass spectrometry and atomic absorption spectrometry for trace analysis of nearly pure solid materials. He is the author of several articles on electrochemistry and fuel cells in technical publications. He is a senior member of the American Chemical Society and was a National Science Founda!ion Fellow in 1952-53 and a Du Pont Fellow. 1953-54. He was co-chairman of the 1964 Gordon Research Conference on Electrochemistryand Chairman of the 1965 Conference

ionic mobilities, the expected time constants have been catalogued (44). It is likely that activity step responses can show all or any of the time constants depending on fortuitous degeneracies. Unfortunately real electrodes are not ideal: and many factors such as heterogeneities, microcracking, high resistance surface layers, high resistance grain boundary surfaces. a n d other unrecognized processes, conspire to complicate time responses. Among the known, or a t least presumed, factors is slow, potential-dependent interfacial ion transfer corresponding to an “activation” overpotential and an “activation” resistance. Since this resistance is in series with bulk membrane resistance, its measurement is difficult. However, Cammann a n d Rechnitz (60) find some evidence for smaller-than-supposed exchange current densities. T h e fastest process (shortest time constant) one expects to measure is geometric charging where T is the product of geometric capacitance and high frequency resistance for one-dimensional transport in membranes. One expects and finds (88) silver electrodes to respond to very rapid concentration steps more rapidly than the higher-resistance silver salt membrane electrodes. For solid film-free electrodes, the longest time constant for step concentration changes is that required to produce uniform bulk concentrations u p to the electrode surface. For many liquid membranes and filmed electrodes (intentional supports, hydrated or precipitation films), finite diffusion through the highest resistance layer determines the long-time constant. In this work (88), observation that responses depended on bathing solution activity suggests some involvement of the long-time constant process (287). Buffle and Parthasarathy (53, 315) have also derived the long-time constant expression and the surface kinetic time constant. Their experiments verify the solution transport character of the long-time process and hint at surface kinetics, (not verified by single crystal measurements (48)). Elegant experimental time responses are by Shatkay (364) and by Lindner, Toth, and Pungor (249). The latter work brings out the very good practical point that membranes need not be uniform and that different time courses of potential-generating processes may occur at different poinb on an electrode surface. Instead of modeling electrode responses as a series of parallel RC elements, sume parallel aggregates of series RC elements may be present also. Morf has also proposed a theory and model for transient responses when inhomogeneities are present (285). Surface studies using electron micrographs to detect Ag and I, presumably as AgI in functioning and poorly functioning silicone rubber-based electrodes have been described (261). T h e question of normal behavior of silver halide membrane electrodes a t low activities of both component ions has been resolved (79: 231). T h e detection limits are determined by salt solubilities. Baucke’s work (27. 28) confirms the theory that for Ag/AgCl, all-solid-state and 2nd kind electrodes using the same materials should behave identically. Another problem solved for a specific case is the presence of faradaic

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involvement (oxygen half-cell) a t the interface between an ionic conductor (Ca di-n-octylphenylphosphate in PVC) contacting Ag, Ag/AgCl. and Teflonized graphite (188). Other examples of ion exchanger/metal electrodes have appeared (198). In one case, Dowex and Amberlite resin powders are coated onto platinum using Neoprene AD. While not Nernstian, responses to increasing anion and cation activities are directionally correct. An example showing a clear faradaic process is Dowex anion exchanger in 1,- form contacting P t . This electrode responds to 1- activity (303). I have pointed out before how important reversible exchange of electrons or ions a t a salt/metal interface is for creating a reproducible Galvani interfacial potential difference. Those salts which perform well in all-solid-state configuration have significant electronic, as well as ionic conductivity. A continuing program by Vlasov and associates has produced results on ionic and electronic conductivities and transference numbers for silver halides, mixed Ag,S-AgX and .4gX--Hg2& systems using pressed pellet samples and single crystals where possible (420-422). It has been said before in these reviews t h a t electrodes containing oxidizable anions may be sensitive to air oxidation in solutions of low activities of sensed ions. According to Midgley (277),production of Cuz+ can occur with Cul,&3e, CuS-Ag,S, and Cu2+-sensingSelectrodes in response to oxygen content and pH of solutions. I t may be that responses of CuS-Ag,S to chelating compounds in titrations, but without added Cu2+,arise from either air-oxidation of lattice anion to free CuZt, or by competitive solubilization (309). It has been said before that Cu*+-selectiveelectrodes of mixed sulfide type are sensitive to C1- and F-. Midgley has investigated Cl-- and F--caused shifts of Eo and finds a dependence on surface conditioning (278). Other workers find a linear, but nonNernstian calibration for Cu2+in C1- media (307). New intercomparisons of potential-activity responses, potentid-time responses and interference-selectivity studies for three commercially available Cd2+electrodes and two Pbe+electrode have been published (225, 226). A very careful study of t h e responses of solid-state cation-responsive TCNQ radical anion electrodes demonstrated that the lower limit of cation detectability was (cation”’) (TCNQ-), solubility. Interferences correlated exactly with an ion-exchange mechanism (363).

CHEMICALLY SENSITIVE SEMICONDUCTOR DEVICES (CSSDs) Ion selective field effect transistor (ISFET) research has been routinely reported in these biennial reviews since Bergvelt‘s first paper appeared eight years ago. T h e most recent paper is 1976 (35). In the past few years electrochemists and solid-state physicists have faced each other across the table with sufficient understanding that communication and even joint efforts are possible. The most complete discussion of the devices presently known and being publicly considered is in the proceedings of the workshop on theory, design, and biomedical applications of solid-state chemical sensors (67). A single review which brings out both the chemistry and physics of CSSDs is by Janata and Moss (197). The first paper which laid out the fundamental relationships for ISFETs between activities, field, potential profiles, and charge was presented by Kelly (213) a t a conference in Newcastleupon-Tyne in January 1976. Prior to this. physical aspects had already been discussed by Zemel (430.431)?and working devices for analytical purposes (including the need for reference electrodes) were demonstrated by Moss, Janata, and Johnson (290). From the theory and practice of MOS capacitors, gatecontrolled diodes and MOSFETs, a necessary condition for the sensitivity of the devices is that a field be transmitted through an insulating gate and be terminated in a space charge region a t the gate/semiconductor interface. In MOSFETs the field is created by the charge on the metal gate, but in general, fields can be created in OSFETs(M0SFETs without metal) by any of several-processes of ion exchange, including ionization of neutral groups such as SiOH, electron exchange, adsorption of charged species, or alignment of dipoles a t the external gate surface. These processes may be enhanced, made to occur. or controlled by exposing the OSFET to reactive gases, solvent, and electrolytes, redox reagents, or by coating the OSFET with reactive layers such as ion exchangers and

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___ Table 11. Solid Electrodes for Both Anion and Cation Analyses Part A. Electrode Formats Halide-selective electrodes made from thin films of AgX or Ag,S; 1. Ag,PO, on Ag,,I, jP,O, responsive to HPO, 2 - ; other examples in patent. Halide-selective AgX-film 011 pressed Ag powder and Ag metal. 2. AgX.Ag,S mixtures on Ag; PbS and Pb, Ag,Te-MnTe-Mn 3. Halide-selective AgX-film on glass with metal contact. 4. Ag t heavy metal oxide, fired on glass substrate. 5. Improved membrane claimed by melting Ag,S-AgC1. 6. Cl--sensitive micro-pipet tip electrodes using in-situ generated AgC1. 7. NO,--sensitive solid electrode from a membrane of silver 8. diethyldithiocarbamate-Nernstian from to 1 0 - 1 M, pH 4-11, Halide-selective (Br-, Cl-, SCN-, C N - ) electrodes based on Hg(1) 9. salts and Hg, S. Comparison with corresponding silver-based electrodes. Solid-state electrodes based on Ag or Hg sulfide, selenide, and 10. telluride matrices. Includes electrodes for halides and heavy metal cations. Transition metal electrodes are unsatisfactory, as expected. Br--selective electrode from Hg,Br, -Hg,S 11. Sulfite-sensitive electrode from melted AgC1, Hg,Cl,, and Ag,S. 12. Single-crystal Cu,S and a study of responses t o Cu(1) and Cu(I1) 13. activities. Copper telluride Cu,.,,Te as a C u i +sensor. 14. Ternary and quaternary compounds of S, Se, and Te with Cu(II), 15. Hg(II), Mn(II), Cd(II), and Pb(I1) and Ge, Sn, and In; studied as possible ISEs. 16. From melts (Cd, Ag)S functions as Cd(I1) sensor; (Zn, Ag)S fails to sense Zn(I1) reliably. Potassium zinc ferrocyanide in silicone rubber responds to K’ 17. activities. Selectivity over Na’ is about the same as commercial cation glass electrodes. Cs and T1 tungstoarsenates in Araldite resin are suggested 18. as selective electrode components. Calibrations are improved in mixed solvents. Another study of SO,’. responses of BaSO, in PVC (approx. 19. Nernstian from 10-4t o 2 x lo-’h l ) . CaWO, and BaMoO. are reported to be responsive to C a z +and 20. Ba2+activities! “Fresh” BiPO, in PVC with dioctylphthalate is said t o be responsive 21 to 10.’ M (18-mV slope). t o PO,’- from UO, ”-t‘etracyanoquinodimethane as sensor f o r U 0 2 z*. 22. Investigations of methods for preparing responsive CuS--Ag,S 23. electrodes. Part B. Applications of Membrane Electrodes Direct measurement of halide interferences with halide-sensitive 1. electrodes, Application t o titrations of mixtures. Titrations of 1 5 anions and determinations of equilibrium constants. 2. Use of Cl--sensitive electrode for formolysis kinetics in nonaqueous 3. solvents. Improving halide detection limits using alcohol-water mixtures. 4. Demonstration of upper response limits of AgI-based electrodes (by 5. dissolution ). Micro and sub-micro determinations of thiocarbonyl and thiol 6. groups using I--electrode. Electrode for detection of H,S using Ag,S, Ag/AgCl (ref), air gap 7. and porous Teflon membrane. Determination of xanthates by pot. titration and Ag,S electrode. 8. Response of Ag,S electrodes t o Cu2+; use in complexometric 9. titrimetry. Cyanide response applications of Ag,S electrodes. 10. Analysis of C1- in high purity water and heavy water using 11. Hg,Cl,-HgS electrode. Potentiometric determination of sulfite with a Hg:Cl,-HgS 12. electrode. Titration of benzyldithiocarbamate with Cu2’ monitored with 13. Cu +-sensitiveelectrode. Extraction rates monitored by Cu2+-sensingelectrode. 14. Use of Cu”-selective electrodes in chelometric titrations-back 15. titrations. Microcell ( 2 5 p L ) Cu2+-selectiveelectrode with standard addition. 16. Use of C d 2 + -and Cu2+-responsiveelectrodes to monitor EDTA 17. titration of VO”. Determination of sulfate by Pb2’ titration: 18. ( a ) in 80% isopropanol with commercial Pb”-sensitive electrode ( b ) using a single crystal PbSe electrode. I


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Table I1 (Continued) Part B. Applications of Membrane Electrodes 19. 20.

Standardization of Cd2+-selectiveelectrode using C d 2 + diethylenetriamine metal-ion buffers by pH control and computer calculations. Triethylenetetramine nitrate, KNO, interference preventive buffer for use with Cu(I1)-responsive electrodes.

redox-sensitive layers. The more subtle generation of surface potentials a t an electrolyte/insulator or electrolyte/metal interface has been discussed in the light of the Esin-Markov effect by Janata and by Buck for dipole and ion adsorption (67). T h e diffuse space charge part of interfacial potential for interfaces with fixed charge (ionized, attached groups, or electrons, or partitioned salts) has been known since t h e Gouy-Chapman theory and many subsequent refinements have been ublished. One recent treatment is by Healy, Yates, White, a n 8 C h a n (159). Solid state physicists overemphasize t h e space charge originating from interior adsorption of charged defects (surface states) and surface-attached ionized groups SiO-. T h e doubly diffuse component is surely present as well for aqueous/immiscible liquid electrolyte interfaces, aqueous/ion exchanger, aqueous/ion conducting solids because ions composing t h e lattice (or oil soluble salt) have different free energies of solvation. One has quite different amounts of space charge generated a t the aqueous KBr/AgBr or aqueous AgN03 AgBr interface for this reason-without invoking any speci characteristics of the AgBr surface-to-bulk region. Reversible interfaces show interfacial potentials established by equality of Fermi energy (electrochemical potentials) of species in equilibrium across the interfaces. Dipoles, surface states, etc. adjust their potential contribution to permit this limit of thermodynamic behavior. On the other hand, blocked interfaces across which no charged species cross, show interfacial potentials established by dipole layers, adsorbed ions, surface attached ionic groups, or all of these. Sub-Nernstian, Esin-Markov behavior is expected in some cases. Schenck has found sub-Nernstian responses for his devices using NaCl (aq.)/SiO, interfaces (350). Revesz has offered an interesting interpretation of interfacial and bulk potentials for controversial monopole CSSDs (337). Buck and Hackleman (47) have investigated a specific MOS capacitor system (better described as an OS-capacitor system) to show that Ag+/AgBr exchange behaves analogously to MOS systems, to relate the measured potentials to corresponding Volta measurements, and to suggest a consistent picture of concentration, potential, and field profiles within the devices. The need for a reference electrodes and its biasing is reported, together with numerous similarities with ion-selective membrane configurations.

LIQUID ION-EXCHANGER MEMBRANE ELECTRODES For reversible, rapid ion exchange (ions of same charge), t h e steady state, segmented potential model interprets membrane potentials and interference responses fairly, in terms of extraction, mobility, and ion pairing, or complex formation parameters. T h e fact that time responses are not just the fast, sin le time constant geometric electrical relation time, does not f e i y t h e theory, because time responses are sensitive to ion pairing in t h e membrane phase. Similarly, selectivity coefficients for significantly ion-paired systems depend on ion-pairing formation parameters as well as the others mentioned. Stover and Buck have treated these dependences in two papers (378, 379). Response time dependence on lability has been mentioned again by Ryan and Fleet (346). Other factors: slow ion-exchange kinetics and formation of inhomogeneous surface layers may also cause slow attainment of equilibrium. In this context, adsorption of charged surfactants and partitioning of salts with oil-soluble cations, but water-soluble anions (or vice versa), cause surface charge density, which slows ion transfer rates. Border-line kinetics should also show u p as sub-Nernstian response for systems with non-zero flux in the steady state (e.g. biionic cases) and asymmetric current-voltage curves for symmetric electrolytes (153). Observations of slow kinetics from this surface-rate control source, compared with slow responses from ion pairing and slow transport in membrane bulk, can be

(80) (202)

“sorted out” using impedance diagrams: e. ., the shapes of Cole-Cole impedance plane plots. Luca and gemenescu (253) have observed these time effects, but they need not frame a new model for the explanation. Very excellent measurements of, and models for, charged ion partitioning across water nitrobenzene were among Frumkin’s last contributions wit his students (38,39, 262). Vibrating plate (Volta potential) measurements have also been made. The charge situation is not simple, and involves both adsorbed and diffuse components (131, 146). Fundamental studies of synthetic polymer ion exchangers and liquid ion exchangers, using biionic potential measurements or back-to-back membrane vs. second kind reversible electrodes, show expected Nernstian responses with good correlations of selectivity with apparent ion extraction coefficients and mobilities (109, 142,204,265,272,365). T h e general Hofmeister cation and anion series (based on dielectric-Born cycle effects) are obeyed, although, minor order reversals occur for different functional group, mediator solvents. It is solvent functional group, size, and steric character t h a t “fine-tunes” selectivity. Outside of gross predictions of selectivity order from the Hofmeister series, there is no a priori theory which allows one to predict precise selectivity orders. I t has been suggested before t h a t impregnation of synthetic resin ion exchangers with organic solvents, should allow some control of selectivity. Unfortunately, synthetic ion-exchanger resins are not readily “wet” by many organic solvents. However, it has been recently shown t h a t a resin with long-chain, alkyl quaternary ammonium sites, when wet with nitrobenzene, behaves similarly to the equivalent liquid membrane (203). In addition (107) Cussler’s group has been able to use porous polymer membranes which retain relatively incompatable aqueous-organic liquids by surface tension. Further test of transport theory is possible using membrane cells with the two sides (bathing solutions) at different temperatures. Scibona et al. have done careful studies of tetraalkylammonium systems (355, 356). A theory (205)of the origin of detection limits with liquid ion-exchanger electrodes has been presented. The idea is that extraction equilibria of counterion-site molecules determines ultimate selectivity. The equation for potential has a solubility term in it which includes the concentration of sites. Formally, the equation is the same as Buck’s equation for solid salt membranes. Hulanicki and Augustowska (184)discussed this problem. Another common hypothesis, of a diffusion layer on the outside of low resistivity membranes undergoing continuous transfer of material from one side to t h e other, has been directly verified using laser interferometry. There have been previous studies of the same type (242). Table 111 contains a selection of liquid ion-exchanger membranes, some applications. and a few fundamental study papers. Many applications were omitted because they were similar to previous publications. T h e electrode composition papers are nearly complete, although I omitted a few in difficult languages and inaccessible journals. Formats were not specified. Some electrodes were porous support (i.e., Millipore type), membrane configuration, or PVC supported. Some used direct impregnation-contact to graphite, Teflonized carbon, or platinum. A number of coated-wire electrodes (PVC-dibutylphthalate mediator) for NH4+ and K+ using BPh,- (177, 178) or PVC-Aliquat for chloro and other halo complexes of Hg(II), Cu(II), Zn(II), and Cd(I1) (62-65), and Ca2+ (351) have been published in this period.

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NEUTRAL CARRIER SYSTEMS Simon’s group is dominant in this field, although contributions to ISE development have been made in Cardiff, Newcastle-upon-Tyne, Prague, and Warsaw. Many additional groups have contributed to synthesis and extraction of neutral carriers or ionophores (54). I n addition to the inspired

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Table 111. Liquid Ion-Exchange Electrode Technology Part A. Monovalent and Divalent Cation Detection 1. Li+-responsiveelectrode uses only (sic) n-decanol. Response comparable to “cationic” glass electrodes. 2. Na+-responsiveelectrode uses monensin; microelectrode construction, 1-s time constant. 3. K+-responsive microelectrodes for bio-applications. 4. Double barreled K’ or C1- selective microelectrodes for bio-applications. 5. Cs+-selectiveelectrodes (BPh; in nitroaromatics). 6. Ca2+-Orionexchanger (92-20-02)in PVC matrix-demonstration via radio Ca2+and C1that membrane is permselective to Ca2+. 7. Ca2+-di-n-octylphenylphosphonate in PVC; responses as function of added solvent mediators. Selectivity coefficients also were determined. 8. Ca2+-selectivefixed site membrane using grafted alkyl phosphate sites on PVC, poly(viny1 alcohol) (copolymer) matrix; no particular advantage over comparable liq. membranes. 9. Cazt-selective electrode optimization using di-n-decyl phosphate in various tri-n-alkyl phosphates. Long chain alkyl groups are preferred --C,,. Failure or poor responses in many nonphosphate solvents is noted. 10. Use of Ca2+-electrodesfor determining Ca2’-complex formation constants for tartrate, malate, succinate, malonate, maleate, and fumarate. 11, Applications of Caz+-responsiveelectrodes for serum-ionized calcium and in whole blood. 1 2 . Hardness response (Ca2++ Mg2t)attributed to a solid, phosphonated polyethylene film electrode. 13. Ni2+-responsel o e 3M [Et,N] ,[NiL,], L = 5,6-dithiobenzo-86-dithiobenzo-7,8-phenazine in nitrobenzene, Fez+,Cu2+,Co2+are minor interferences. 1 4 . Zn2+-responsivepolymeric membrane electrode resembling a Ca2+-sensingelectrode; C a z +is removed by F - precipitation. 15. Pbzt-responsive membrane electrode based on Pb diisobutyl dithiophosphate. 16. Pb2+-responsivePVC membrane electrode using diethyldithiocarbamate in tetrahydroiuran. 17. TI+-responsive membrane electrode based on 0,0’-didecyldithiophosphatein chlorocyclohexane. 18. Ag+-responsivemembrane electrode using a very complicated chelating thiotriazine in CHCI,. 1 9 . Cu2+-responsivemembrane electrode using pyrrolidine dithiocarbamate in CHC1,. 20. Cu2+and Hg2+-responsivemembrane electrodes using diphenylthiocarbazide, Ruhemann’s Purple, and salicylaldoximate in CHCI,. Interferences were studied. 21. Hg2+-selectiveelectrode application to EDTA titrimetry. 22. PVC electrodes responsive to Hg2+,Zn”, Co2+,and Ni” based on oil-soluble complex salts M2+(NL,)”, L = SCN-. Part B. Inorganic Anion Detection 1. PVC NO,--responsive electrode compositions: various tetraalkyl ammonium nitrates in dibutylphthalate. Alkyl groups are C, and larger. 2. NO, --responsive electrodes using gentian violet or tetraphenyl phosphonium bromide in nitrobenzene or in tetrachlorethane. 3. NO, --determination via electrode and colorimetry compared. With precautious, electrodes are satisfactory! 4. NO,--determination in difficult systems HNO, -HF pickling baths-use standard addition. 5. NO,--determination compared with official 1st action AOAC method 24037-24038. 6. CIO,--responsive electrodes based on methylene blue in nitrobenzene and related solvents (lo-‘ to 1 M ) . 7. PVC-(210,--responsive electrode based on tris(bathophenanthroline)iron(II). 8. Titrimetry of C10,- using Ph,AsCI or Ph,PCI gives nearly equivalent results; lower limit -2 x M. 9. Applications of IO,-(ClO, -)-responsive electrodes in monitoring analytical reactions of IOa with carbohydrates, glucose, ol-aminoalcohols, etc. 10. ReO,-(ClO,-)-responsive membrane electrodes using quaternary phosphonium salts in nitrobenzene and dibutylphthalate. 11. Reo;, SbCI;, TlCI;, AuCl;, and anionic dye-responsive systems based on cationic dyes. 12. BF,--responsive membrane electrodes based on Ph,PBr in tetrachloroethane. 13. ClO,--responsive quaternary alkylammonium electrodes. Expected interferences by NO, -, I - , ClO,-, SCN-, etc. 14. Cr0,2‘-sensitive membrane electrodes based on crystal violet in nitrobenzene; also reported response of HCrO, €or tetradecylphosphonium in an organic solvent. 15. FeCI, --sensitive membrane electrodes using triphenyl-pyrilium cation (preferred ) in dichloroethane. Other extractants were studied. 16. AuC1, ‘-sensitive membrane electrodes using complex extracting agent. 17. AuCI,- and Au(CN),--responsive electrodes based on Ph,As+ Part C. Organic Anion-Detection 1. Simple monocarboxylic acid (C, -C,), benzoic, and substituted benzoic acids responses of quaternary ammonium and metal ligand cationic-site membrane electrodes. 2. Phenobarbital-responsive coated wire membrane electrode. 3. Chromazurol-S- and Eriochrome Black T-responsive membrane electrodes. 4. 2,4-Dichlorophenoxyaceticacid, and 8-quinolinol-5-sulfonate-responsive membrane electrodes. 5. Bile salt anions (taurocholate, taurodeoxycho1ate)-responsivemembrane electrodes. 6. Dodecylsulfate-ion responsive membranes based, respectively, on alkyl-dimethylbenzylammonium cation ( 3 2 4 ) ,rosaniline ( 2 6 9 ) ,ferrousorthophenanthroline (8, 70). Closely related dodecylbenzenesulfonate electrode used o-phenanthroline cobalt(II1) ( 9 ) .

(167, 268, 3 1 1 ) (61) (208, 334) (158, 3 8 0 ) (133)


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Table IV. Neutral Carrier Systems and Electrodes 1 . Ionophores for alkali and alkaline earth ISEs, preparation, testing in PVC with mediators

o-nitrophenylether or dibutylsebacate. 2. Synthesis of neutral ionophores for Ca2- membrane electrodes. 3 . Neutral ionophore for liquid membrane electrodes with high selectivity for Na’ over K’. 4. Neutral carrier for Ba2+. 5. Poly(propy1ene oxide) neutral carriers for Ba2+with tetraphenylborate in PVC and dioctylphenylphosphonate mediator. Also, studies of mediator effects. 6 . Anitibiotic A23187 in nitrobenzene, held in cellulose ester membrane as electrode responsive to Ba2+(and to lesser degrees alkaline earths, except Be). 7 . Nitrogen-linked (through pyromellitic diamide) cyclic polyether (crown types) for ion binding. stabilities in water. 8. Potentiometric titration studv of alkali metal ion crvatate *. 9 . Synthetic ligand selectivities ?or Ca2+and Na’ used in lipid bilayers to enhance conductance, were consistent with selectivities of thick membranes. 10. A review of development and characterization of synthetic carriers. 11. Micro-electrode for K’, based on valinomycin and applications to plasma analysis. 12. K’selective valinomycin-based electrode in polycarbonate, siloxane copolymer. 13. K+-selectivecrown ether electrode, PVC and dipentylphthalate mediator. 1 4 . Identity of Crytur K+-sensitiveelectrode as valinomycin-based, using dipentylphthalate. 15. Anion interference removal for Kval’ electrode uses low dielectric solvent and fixed negative site surface-coated support. 16. Anion interference characterization and means for partial removal. Electrodes use valinomycin and crown ethers in PVC. Improved responses were found by using alkyl chain phthalate mediators. 17. Optimizing solvent mediators for Na’, K’,and Ca2+responsive polymeric electrodes. 18. Neutral carrier Li+-responsive PVC membrane electrode and microelectrode. 19. Neutral carrier Ca2+-responsivePVC membrane electrode and microelectrode. 20. Application of ISEs to study lipid bilayer behavior-review with 135 references. Table V. Enzyme Electrodes o r Systems and Bio-medical Applications of ISEs 1. 2. 3. 4. 5.

6. 7.

8. 9. 10.

11. 12. 13.

14. 15. 16. 17.

18. 19.

20. 21.

22.

23.

For 5’-adenosine monophosphate (AMP). AMP-metal complexation and thermodynamic quantities. AMP-d-fructose-1,6-diphosphatase binding. Automated analysis of adenosine deaminase using enzymes and NH, -sensing electrode. Electron transfer electrodes (Pt, Au, C ) using lactate dehydrogenase and ferricyanide for lactate analysis. Electron transfer enzyme-covered Pt electrode for determining blood lactates via cytochrome b , and ferricyanide. Lactose, sucrose, and maltose analysis using PO, electrodes and appropriate enzymes, For creatinine (urine and serum). For L-arginine and L-lysine using decarboxylase and CO,*--sensitive electrode. For L-asparagine in conjunction with enzyme and NH, sensing electrode, For L-phenylalanine in conjunction with enzyme and N H , -sensing electrode. For urea in whole blood using enzyme with NH,-sensing electrode. For uric acid with immobilized uricase and pC0, electrode. For SO,*- by amperometric interference of 4-nitrocatechol oxidation on Pt. Uses 4-nitrocatechol sulfate and arylsulfatase. PO,)- also inhibits the oxidation. For phosphate: two enzyme systems using amperometric monitoring. For nitrite using nitrite reductase (to NH,) and “,-sensing electrode. Construction patents for immobilized enzyme electrodes, Acetylcholine-ATP binding using a liquid ion exchanger selective for acetylcholine. Dibenzyl-dimethylammonium-selectiveelectrode using tetraphenylborate in dichloroethane as liquid ion exchanger. Hapten-responsive liquid ion exchanger electrode using trimethylphenylammonium ion sites. Application in immunochemistry. Immuno-monitoring using indirect reactions and release of marker reagent. Patent on Janata‘s “Immuno-electrode”. Further studies o n protein responses of silver sulfide membrane electrodes.

synthesis of selective carriers, Simon’s group has characterized chemical systems: (1) determined stability constants (in ethanol) for many alkali a n d alkaline earth ion-carrier complexes (223);(2) used 13CNMR to show rotational mobility of complexes (50) and non-involvement of C = 0 in some cases

( 5 1 ) ;and (3) shown ion pairing with lipophilic anions (52). The question of mechanism of function of neutral carrier electrodes has been relegated to minor importance because it is difficult to choose between two appealing models. Everyone agrees, including the Russians (259), t h a t t h e lipid

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Table VI. Potentiometry and Ion-Selective Electrode Nomenclature (The following list of terms, their definitions, and abbreviations is based on current usage consistent with recommendations of IUPAC Divisions of Analytical and Physical Chemistry (1-5) Two exceptions are marked with *). General Potentiometry, Differential Potentiometry, Potentiometric Titration, Differential, Derivative, and other variant Potentiometric Titrations. See def’s. 4.1-4.7 ( 6 ) Galvanic Cell Organization and Potentials defined, illustrated with recommended symbols ( 7 ) Equilibrium between Two Charged, Simple Phases, definitions and symbols (8) Activities, Activity Coefficients, Concentrations, Electrolyte Solutions and Related Quantities. definitions and svmbols 15. 9 i

Cu (left)

External reference electrode: typically mercury-calomel or silver-silver chloride in fixed activity C1-

Salt bridge

External monitored solution

Membrane, reversible and permselective to cations or anions

crystalline, primary, homogeneous electro de-“solid” elect rode, e.g., single crystal, pressed pellet, or melted pellet AgC1, or AgCl-Ag,S crystalline, primary, heterogeneous electrode-“solid” electrode e.g., AgCl powder in PVC, o r a AgCl Selectrode, AgClihydrophobized graphite. detection limit, drift, hysteresis- see ( 3 ) electrode kind, type or class (equivalent terms): *zeroth-redox only, e.g., Pt/Fe(CN), 4 - , Fe(CN), 3 first-one ion-crossing interface, e.g., Ag/Ag+ second-two involved ion-crossing interfaces, e.g., Hg/Hg,Cl,/C third-three involved ion-crossing interfaces, e.g., Pb/PbC,0,/CaC,0,/Ca2+ electrodes, membrane-half-cell including phase separating electrolyte solutions such that ordinary charge transport is modified and potential differences are created, e.g., 2interface ion-exchanger phase with inner reference as in cell (above). All-solid-state configurations omit inner filling solution and connect common metal wire to salt. electrodes; reference-a nonpolarizable half-cell of known or reproducible potential difference, e.g., usually second kind electrodes such as Ag/AgCl/Clmediator-a solvent added t o non-exchanger membranes to modify ion selectivity coefficients

bilayer theory is inappropriate to electrodes which are overall electroneutral, “thick” membranes. One view assumes, for t h e Kval+ electrode as an example, that anions from the solution or OH- from water provide the counter charge in the hydrophobic organic membrane matrix (288, 390). On the other hand, fixed sites or mobile sites may arise from the organic membrane solvent and support (or mediators in the case of PVC membranes) via impurities hydrolysis or air oxidation (211,321). T h e neutral carrier has the important functions of enhancing single-ion extraction coefficients of ions which bond strongly with the carriers, insulating easily hydrated ions such as alkali cations from the hostile lipophilic membrane, and conferring special mobility to the complexed species.

nonblocked interface, nonpolarizable interfacerapid, reversible ion exchange, potential differencedefined inter face noncrystalline, primary electrodes-general term for porous, supported (e.g., Millipore filter, glass frit) and nonporous (e.g., PVC) liquid ion exchanger, neutral carrier, solvent mediated membrane electrodes. May include mediators and gelling agents. Also defines glass membrane electrodes potentiometric selectivity coefficient - kK$ used in potentiometric response equation potentiometric response equation-historically a form closely connected with Horovitz, Nicolsky, and Eisenma It is vaguely a form of Goldman-Hodgkins-Katz equation or Nernst equation. When response to only one ion is involved, and is ideal, Le., obeys the following equation, the response is called “Nernstian”. *E = const. + 2.303 RT/F log [ u A l i Z At (kr;Oi a g ) I i z R ] E is cell voltage (SI unit V). The response foi the two

Inner filling solution containing a fixed activity or permselective ion and fixed C1activity

AgC1; Ag; Cu (right)

difference, or emf found by (right)--’&, (left) and this quantity has thermodynamic significance in the absence of liquid junction potential differences sensitized ion selective electrodes-gas-sensing and enzyme substrate electrodes. An interposed chemical reaction is involved with conversion of sensed substance or intermediate to a product ion detected by the underlying electrode. References (1) IUPAC, “Classification and Nomenclature of Electroanalytical Techniques, Pure Appl. Chem., 45,81(1976 ( 2 ) IUPAC, “Manual of Symbols and Terminology”, App. I11 Electrochemical Nomenclature, Ibid., 37, 501

(1974). ( 3 ) IUPAC, “Recommendation for Nomenclature of Ion-Selective Electrodes”, Ibid.,48, 127 (1976). ( 4 ) IUPAC, “Manual of Symbols and Terminology”, Butterworth, London, 1973 ( 5 ) IUPAC, “Proposed Terminology and Symbols for the Transfer of Solutes from One Solvent to Another’ Information Bull, No. 34 (August 1974). ( 6 ) Ref. (l), p 86. ( 7 ) Ref. ( 2 ) , p 504-506; ref (4),pp 9-10, 27-28. (8) Ref. (2), pp. 507-508. ( 9 ) Ref. ( 2 ) , pp 510-511; ref (4), pp 36-40. ( 1 0 ) Ref. (4),p p 29-30. ___ Data on membrane potential development and salt extractabilities by essentially inert or, a t least uncharged, materials are constantly appearing. This topic deserves some further investigation theoretically and experimentally. For example, amyl alcohol shows proton activity response in membrane configuration with HC1 bathing solutions. However, tribenzylamine above 0.01 % converts the membrane to anion selectivity. Responses improve with additional amine to about 0.5%, then decrease in slope up to the limit of 40% as studied by Licis (245). He has also studied Fe3+ transport and found similar unexpected responses (246). Astrom (14) found that chlorinated solvents in millipore filters cause response to anion activities, without added ion exchanger! If one accepts the hypothesis that the low dielectric solvents


used conventionally for neutral carrier-based electrodes contain mobile sites, then potentiometric responses should give clues. Buck, Stover, and Mathis worked out the general theory for potential responses for low-site concentration membranes over the range of bathing activities where co-ion exclusion will fail (Donnan Breakdown) (49). For negative sites, varying salt activity on one side, peak responses or two-slope responses (same sign, different magnitudes) are found depending on relative anion (co-ion) to cation (counterion) mobilities. Examples of systems with peak responses are common; two-slope responses have recently been reported (201). T h e theoretical relationships always relate slopes or peak positions to site concentration divided by salt partition coefficient. Alternate ways of determining site existence via charge measurements have been suggested by Demisch and Pusch (89). Neutral carrier system studies and neutral carrier-based electrodes are listed in Table IV.

BIO SYSTEMS AND BIOMONITORING T h e impact of ion-selective electrodes in biology and medicine has been primarily in clinical laboratory measurements. T h e use of alkali and alkaline earth-sensitive electrodes for in vitro measurements is well documented. In addition, the various enzyme-based electrodes, including gas-sensing electrodes, have made new batch analyses possible. Progress in this area is summarized in Table V. In the long run, continuous monitoring in vivo and bed-side care applications will be the areas for major ISE applications. Already, there are continuous systems reported in the literature and for sale. Whether membrane configuration, all-solid-state, or ISFET formats prove to be more useful, remains to be seen. Microelectrode design and use in electrophysiology and pathology were described in a meeting sponsored by the German Forschungsgemeinschaft (215). There have been subse uent meetings and these will continue with worldwide contr8utions. Among the readily available literature in English are patents on design of subtle miniature sensors for p H using Pd/PdO, COPusing P d i P d O or Ir/IrO coated with COz-permeable polymer, and K' using valinomycin (258,298, 299). Fleet, Bound, and Sandbach have reviewed miniaturization of coated wire sensors and enzyme-based sensors, especially emphasizing sensors for Ca2+,NH4+,K', and Pb2+ (113). Micro electrodes for K+, Na', and C1- for in vitro work are reported (43). These are improved versions of ion-exchanger-filled pipet tip electrodes already described. Extraordinary 4-barrel micro-tip electrodes have been made and used also (216). An all-solid-electrode for in vivo K' has been described (81), and a patent issued for a complete ion measuring system for living tissue applications (280). A successful, membrane configuration, catheter K' electrode has been recently described (24,25,400). Measurements using surface electrodes for sweat testing (the Orion 96-17-01 system) have been reported (41, 42). Continuous blood gas and ion-activity measurements on whole blood or serum are fashionable. Fuchs and co-workers have been doing Ca2+in serum routinely using flow-through electrodes (125). Fuchs and McIntosh (127)dispute the claims of Schwartz (352, 353) t h a t pH-adjusted (by COz, aerobically-handled serum samples give superior analytical results with the commercial AMT apparatus, as compared to Fuch's methods. Schwartz sticks to his guns, however (354). Simon and E T H colleagues have described a flow-through system for clinical analyses, using many neutral carrier and other liquid electrodes (310). The rumored King's College Hospital blood parameters analyzer has also been described (168). Durst (102)has described an analyzer for Na+ and K+ in whole blood. There is a patent on the design of a special curved glass electrode for monitoring serum urea via conversion to NH3 (424). Monitoring of pC0, usin a p H glass electrode (312), a p H redox electrode (415),a n f a PCO,~-electrode (336) is reported. Repetitive titrimetry of ferricyanide, cytochrome bl and c using coulometrically-generated (pulsed) oxidants and reductants has been described (162, 163).

CONTINUOUS INORGANIC MONITORING AND CONTINUOUS TITRIMETRY Because of the large numbers of analyses described in the literature, I have picked mainly English language articles.

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Many reviews on special topics in this field are given in the first section of this review. Alexander has reviewed on-line applications of ISEs in comparison with voltammetric methods (4). ISEs and coated-piezo-crystals have been compared (371). Some continuous monitoring includes Ca2+and NO3- (- 100 ppm level) (187),CN- in waste water (170),removal of sulfide interference using H 2 0 2(122),K+ and NO3- in nutrients (114), pH, pC1 in water supplies (83, 416, 417), pH, pNa, pS2- in pulping liquors (381),pS2- in stri per effluent and steam condensate (149),pNa in natural anatreated water (344),NH, in seawater (276),and river water (155),a t trace levels in water (368),SO2 and O3 using I--sensing electrodes (264),S O z by p H shift (199),Cu2+in seawater (338) and in natural waters (36). Apparatus for continuous monitoring with standard addition or reagent additions are becoming more common. A computer-controlled standard addition potentiometry system was described by Ariano and Gutknecht (12). An internal reference ion system (called tag ion) and two ISEs monitoring tag and the ion being determined (analyte), provide a difference signal independent of flow rate (341). Carr's group has developed a pH-stat using coulometrically generated base (or acid). The time constant is 2-3 s and no overshoot or ringing is observed ( I ) . Pungor's group has pioneered in one aspect of continuous analysis: development of novel titrant generation schemes for adding reagents to streams with injected samples (331,396). Coulometric-generated and injected reagents are used for calibration of ISEs and as reactants in flowing systems (150. 182,397). Compatable with this topic is the computer data acquisition, data treatment, and graphic presentation systems created by Frazer and co-workers (121). This system makes interpretation of titration curves a joy, and a source of kinetic as well as thermodynamic data. Linearization of potentiometric-activity data (for better end-point determination precision) can be done with Gran rulers (4261,special plotting paper (340),and antilog converters (414). Finally, Pungor has reviewed ISEs and voltammetric detectors for chromatography (247,329).Some recent patents cover Ag2S and Pt sensors in chromatography (230, 376). For potentiometry and ion-selective electrode nomenclature, see Table VI.

ACKNOWLEDGMENT The author recognizes the assistance of David Gutterman and Harvey Gold. The search was performed on key words using Chemical Abstract tapes. If papers used ISEs, but obscured the fact in the selection of key word descriptors, then I am sorry. LITERATURE CITED (1) R. E. Adams, S.R. Betso, and P. W. Carr, Anal. Cbem., 48, 1989 (1976). (2) N. Akimoto and K . Hozumi, Bunseki Kagaku, 25, 554 (1976) (Jpn.). (3) L. Alcacer, M. R. Barbosa, R. A. Aimeida, and M. F. Marzagao, Rev. Port. Quim., 15, 192 (1973). (4) P. W. Alexander, R o c . R . Aust. Cbem. Inst., 43, 358 (1976). (5) G. Ambiard and C. Gavach. Biocbim. Biopbys. Acta, 448, 284 (1976). (6) D. Ammann, R. Bissig, M. Gueggi, E. Pretsch, and W. Simon, Helv. Cbim. Acta, 58, 1535 (1975). (7) D. Ammann, M. Gueggi, E. Pretsch, and W. Simon, Anal. Lett., 8, 709 (1975). (8) D. Anghei and N. Ciocan, Colloid Po/ym. Sci., 254, 114 (1976). (9) D. F. Anghel and N. Ciocan, Anal. Lett., I O , 423 (1977). (10) V. F. Antonov, A. S. Ivanov, E. A. Korepanova, and V. V. Petrov, Itogi Nauki Tekb. Biofiz., 5 , 166 (1975) (Russ.). (1 1) J. Antson and T. Suntola, German Patent 2626 277 Dec. 30, 1976; Appi. 75/1773 Jun. 13, 1975. (12) J. M. Ariano and W. F. Gutknecht, Anal. Cbem., 48, 281 (1976). (13) W. M. Armstrong, W. Wojtkowski and W. R. Bixenman, Bbcbim. Biopbys. Acta, 485, 165 (1977). (14) 0. Astrom, Anal. Chim. Acta, 80, 245 (1975). (15) H. Bach, J . Non-Cfyst. Solids, 19, 65 (1975). (16) P. L. Bailey, Glass Tecbnol., 17, 49 (1976). (17) P. L. Bailey, "Analysis With Ion-Selective Electrodes", Heyden, London 1976, 240 pp. (18) G. E. Baiulescu and V. V. Cosofret, "Applications of Ion Selective Membrane Electrodes in Organic Analysis", Halsted, New York, N.Y., 1977, 250 pp. (19) G. E. Baiulescu and N. Ciocan, M a n t a , 24, 37 (1977). (20) G. E. Baiulescu, V. V. Cosofret, and C. Cristescu, Rev. Cbim. (Bucharest). 28, 429 (1975) (Rom.). (21) G. E. Baiuiescu and V. V. Cosofret, Rev. Cbim. (Bucharest),26, 1051 (1975) (Rom.). (22) G. E.'Baiulescu and V. V. Cosofret. Talanta. 23, 677 (1976). (23) G. E. Baiulescu and V. V. Cosofret. Rev. Cbim. (Bucharest),27, 158 (1976) (Rom.). (24) D. M. Band and T. Treasure, J . Pbysiol.. 286. 12P (1977). (25) D. M. Band. J. Kratochvil, and T. Treasure, J . Pbysiol., 285. 5P (1977).

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(26) F. G. K. Baucke, J . Non-Cryst. Solids, 19, 75 (1975). (27) F. G. K. Baucke, J . Electroanal. Chem., 67, 277 (1976). (28) F. G. K. Baucke, J . Electroanal. Chem , 67, 291 (1976). (29) F. G. K . Baucke, Ref. 215 p 77. (30) F. G. K. Baucke. Phys. Non-Cwst. S o l ~ sint. , Conf., 4th 7976, 503 (1977), G. H. Frischat (Ed.). (31) E. W. Baumann, Anal. Chem., 48, 548 (1976). (32) E. Baumgartner and R. Fernandaz-Prini, Rev. Iberoam. Educ. Quim.,5 , 89 (1974) (Span.). (33) C. G. Beguin and C. Coulombeau, Anal. Chlm. Acta. 90, 237 (1977) (Fr.). (34) H. Berge, U. Gruenke, P. Hartmann, R. Scheutze, and D. Stojan, German Patent (East. Ger.) 112314 Apr. 5, 1975; Appl. 178536 May 16, 1974. (35) P. Bergveld, Biomed. Eng., 11. 359 (1976). (38) W. J. Blaedel, G. W. Schieffer, R. A. Niemann, and D. E. Dinwiddie, Tech. Rep. Univ. Wisconsin, Water Resour. Cent WISWRC 76-01 (1974). (37) R. Bloch and E. Lobel, "Membrane Separation Processes", P. Meares, Ed., Elsevier, Amsterdam, The Netherlands 1976. p 477. (38) . , L. I. Boauslavskii. A. N. Frumkin. and M. I. Guaeshashvili. Elektrokhimiva. 12, 856 ( i 9 7 s ) (RUSS.). (39) L. 1. Boguslavskli, V. S. Krilov. and Y. A. Shchipunov, Biofizika, 21, 266 (1976) (Russ.). (40) V. S. Bobrov, V. V. Murshova, and M. M. Shults, Zh. Prikl. Khim. (Leningrad), 50. 1257 (1977) (Russ.). (41) . . P. Brav,'G. C: F. Clark, G. J. Moodv, and J. D. R. Thomas, Clin. Chim. Acta, 77, 69 (1977). (42) P. T. Bray, G. C. F. Clark, G. J. Moody, and J. D. R. Thomas, Clin. Chim. Acta, 80, 333 (1977). (43) A. M. Brown and D. L. Kunze, Adv. Exp Med. Biol. 1974, 50 (Ion-Sel. Microelectrodes), 57. (44) R. P. Buck, Crlt. Rev. Anal. Chem.. 5 , 323 (1975). (45) R. P. Buck, Anal. Chem., 48, 23R (1976). (46) R. P. Buck, J . Nectroanal. Chem., 83, 379 (1977). (47) R. P. Buck and D. E. Hackleman, Anal. Chem., 49, 2315 (1977). (48) R. P. Buck, D. E. Mathis, and R. K. Rhodes, J . Electroanal. Chem., 80, 245 (1977). (49) R. P. Buck, F. S. Stover, and D. E. Mathis, J . Electroanal. Chem., 82, 345 (1977). (50) R. Buechi, E. Pretsch, and W. Simon, Helv. Chim. Acta, 59, 2327 (1976) (Ger.). (51) R. Buechi, E. Pretsch, and W. Simon, Tetrahedron Let?.. (20) 1709 (1976). (52) R. Buechi. E. Pretsch, W. E. Morf, and W. Simon, Helv. Chim. Acta, 59, 2407 (1976) (Ger.). (53) J. Buffle and N. Parthasarathy, Anal. Chim. Acta, 93, 111 (1977). (54) W. Burgermeister and R. Winkler-Oswatitsch, "Topics in Current Chemistry 69", Znorg. Blochem., 2, 9 1 Springer Veriag, New York, N.Y., 1977. (55) J. 0. Burman and G. Johansson, Anal. Chim. Acta, 80, 215 (1975). (56) R. E. Burrell, Ind. Pollu?. ControlMeas. Instrum., Proc. Spec. Conf. 1976. 263. (57) A. S. Bychkov. 0. M. Petrukhin. V. A. Zarinskii, and Y. A. Zolotov. Zh. Anal. Khim., 30, 2213 (1975) (Russ.). (58) A. S. Bychkov, 0 . M. Petrukhin, V. A. Zarinskii, Y . A. Zoiotov, L. V. Bakhtinova, and G. G. Shanina, Zh. Anal. Khim., 31, 21 14 (1976) (Russ.). (59) M. Cakrt, J. Bercik, and 2. Hladky. Fresenius' Z Anal. Chem.. 281, 295 (1976). (60) K. Cammann and G. A. Rechnitz, Anal. Chem., 48, 856 (1976). (61) G. D. Carmack and H. Freiser, Anal. Chem., 49, 1577 (1977). (62) R. W. Cattrall and C. P. Pui, Anal. Chem., 48, 552 (1976). (63) R. W. Cattrall and C. P. Pui, Anal. Chim. Acta, 83, 355 (1976). (64) R. W. Cattrali and C. P. Pui, Anal. Chim. Acta. 87, 419 (1976). (65) R. W. Cattrali and C. P. Pui. Anal. Chim. Acta, 88, 185 (1977). (66) E. E. Chao and K. L. Cheng, Anal. Chem., 48, 267 (1976). (67) P. Cheung, Ed. "Theory, Design and Biomedical Applications of Solid State Chemical Sensors", Proc. of Workshop at Case Western Reserve Univ., March 1977, CRC Press, 1977. (68) J. Chopin-Dumas. R. Mauger, and J. V. Zanchetta, J . Chim. Phys. Phys-Chim. Biol., 73, 946 (1976) (Fr,). (89) H. Clysters, F. Adams, and F. Verbeek, Anal. Chlm. Acta, 83, 27 (1976). (70) N. Ciocan and D. Anghei, Tenside Deterg., 13, 188 (1976); Chem. Abstr., 85, 1 4 5 1 6 4 ~(1976). (71) C. J. Coetzee and A. J. Basson, Anal. Chim. Acta, 83, 361 (1976). (72) M. Cordonnier, F. Lawny, D. Chapot, and D. Thomas, FE6S Let?., 59, 263 (1975). (73) V. V. Cosofret, Rev. Chim. (Bucharest), 27. 240 (1976) (Rom.). (74) V. V. Cosofret, M. Blasnic, and T. Panaitescu. Rev. Chim. (Bucharest), 28, 68 (1977) (Rom.). (75) A. K. Covington and N. Karesh, Anal. Chim. Acta, 85, 175 (1976). (78) A. Craggs, G. J. Moody, and J. D. R. Thomas, Proc. Anal. Div. Chem. SOC., 12, 64 (1975). (77) A. Craggs. L. Keil, G. J. Moody, and J. D. R. Thomas, Talanta, 22, 907 (1975). (78) A. Craggs, G. J. Moody, J. D. R. Thomas, and A. Willcox, Talanfa, 23, 799 (1976). (79) D. J. Crombie, G. J. Moody, and J. D. R. Thomas, Anal. Chim. Acta, 80, 1 (1975). (80) M. Cromer-Morin and J. P. Scharff, C R . Hebd Seances Acad. Sci., Ser. C., 283, 621 (1976) (Fr.), (81) W. Crowe, A. Mayevsky, and L. Mela, A m . J . Physiol., 233, C56 (1977). (82) T. Cserfalvi and G. G. Guilbault, Anal. Chim. Acta, 84. 259 (1976). (83) T. Cserfalvi. T. Meisel. B. Tarnay, K. Seybold, F. Galina, and E. Pungor, Fresenius' Z. Anal. Chem.. 282, 351 (1976). (84) J. D. Czaban and G. A. Rechnitz, Anal. Chem.. 48, 277 (1976). (85) G. Czerwenka and E. Scheubeck, Fresenius' Z . Anal. Chem., 276, 37 (1975). (86) L. D'Angiuro, Ind. Carta, 14, 205 (1976) (ltai.); Chem. Abstr., 85 197537q (1976).

(87) J. P. Deiouma, J. J. Fombon. F. Lancelot, J. Paris, M. Roubin, J. Tacussel. and J. C. Verdier, French Patent 2268 264 Nov. 14, 1975; Appl. 74113272 Apr. 17. 1974. (88) A. Dencks and R. Neeb, Fresenius' 2 . Anal Chem., 285, 233 (1977). (89) H. U. Demisch and W. Pusch. J . Electrochem. SOC.,123, 370 (1976). (90) J. V. Dobson, German Patent 2513613 Oct. 2, 1975; Appl. Brit. 14074/74 Mar . 29. 1974. (91) J. V. Dobson and T. Dickinson, German Patent 2 538739 Mar. 18, 1976; Brit. Aool. 38 748174 SeD. 4. 1974. (92) E. Doktor, J. Havas, L. Kecskes, M. Patko. and E. Pungor, German Patent 2530646 May 6, 1976; Hung. Appl. 623, Oct. 31, 1974. (93) P. D'Orazio and G. A. Rechnitz, Anal. Chem., 49, 41 (1977). (94) P. D'Orazio and G. A. Rechnitz, Anal. Chem., 49, 2083 (1977). (95) E. J. Duff and J. L. Stuart, Analyst(London), 100, 739 (1975). (96) E. J. Duff and J. L. Stuart, Talanta, 22, 823 (1975). (97) E. J. Duff and J. L. Stuart, Talanta, 22, 901 (1975). (98) H. Durlist, M. Comtat, J. Mahenc, and A. Baudras, J . Electroanal. Chem., 66, 73 (1975) (Fr.). (99) R. A. Durst, A&. Exp. Med Biol. 1974, 50 (Ion Selective Microeiectrodes), 13. (100) R. A. Durst, Znt. Corros. Conf. Ser. 1977, Publ. 1974, NACE-3 Localized Corros., 151. (101) R. A. Durst and R. G. Bates, Natl. Bur. Stand. ( U . S . )Spec. Publ., 450, 247 (1977). (102) R. A. Durst Clin Chim. Acta, 80, 225 (1977). (103) C. E. Efstathiou and T. P. Hadjiioannou, Anal. Chem., 49, 414 (1977). (104) C. E. Efstathiou and T. P. Hadjiioannou, Anal. Chim. Acta, 89, 55 (1977). (105) A. M. Elbakai, G. J. Kakabadse. M. N. Kayat, and D. Tyas, Proc. Anal. Div. Chem. SOC.,12, 83 (1975). (106) S. 0. Enfors, N. L. Molin. K. H. Mosbach, and H. J. Niisson, German Patent 2612433 Oct. 14, 1976; Swed. Appl. 75136.52 Mar. 27, 1975. (107) D. F. Evans, M. E. Duffey, K. H. Lee, and E. L. Cusier, Colloid Znterface Sci. ( R o c . znt. Conf.) 5. 119 (1976). (108) N. K. Evseeva, I. N. Kremenskaya, V. N. Golubev, and S. K. Timofeeva, Zh. Anal Khim., 31, 822 (1976) (Russ.). (109) C. Fabiani, Anal. Chem., 48, 865 (1976). (110) U. Fiedler, Anal. Chim. Acta, 89, 101 (1977). (111) U. Fiedier, Anal. Chim. Acta, 89, 111 (1977). (1 12) D. J. Fischer, H. J. Kunz, and T. E. Norby, U.S. Patent 3 923 625, Dec. 2, 1975; Appl 158448, June. 30, 1971. (113) B. Fleet, G. P. Bound, and D. R. Sandbach, Bioelectrochem. Bloenerg., 3, 158 (1976). (114) R. Fleischer and F. Hoffman, Arch. Gartenbau, 24, 445 (1976) (Ger.). (115) D. R. Flinn and K. H. Stern, J . Nectrochem. Soc., 123, 978 (1976). (116) A. G. Fogg, A. A. AI-Sibaai, and C. Burgess, Anal. Let?., 8, 129 (1975). (117) A. G. Fogg and A. A. AI-Sibaai, Anal. Lett., 9 , 39 (1976). (118) A. G. Fogg and A. A. AI-Sibaai, Anal. Lett.. 9, 33 (1976). (119) A. G. Fogg, A. A. AI-Sibaai, and K. S. Yoo, Anal. Lett., 10, 173 (1977). (120) D. J. Fray, Brit Patent 1470558, Apr. 14, 1977; Appl. 74129490, Jul. 3, 1974. (121) J. W. Frazier, W. Selig, and L. P. Rigdon. Anal. Chem., 49, 1250 (1977). (122) P. R. Frei, German Patent 2604803, Jan. 20, 1977: Swiss Appl. 7512544, Feb. 28, 1975. (123) H Freiser, Res.lDev., 27, 28-30, 32-33 (1976). (124) L. W. Frost, U.S. Patent 3 9 5 6 136, May 11, 1976; Appl. 430452, Jan ~

3 -, 1974 .- . ..

(125) C. Fuchs. D. Dorn, C. McIntosh, F. Scheler, and B. Kraft. Clin. Chim. Acta. 67. 99 11976). (126)~C. Fuc'hs, "Ion-Selective Electrodes in Medicine", Thieme, Stuttgart. Ger., 1976, 151 pp. (127) C. Fuchs and C. McIntosh, Clin. Chem. ( Winston-Salem, N.C.), 23, 610 (1977). (128) M. Fujimoto and T. Kubota, Jpn. J , Physiol., 26, 631 (1976). (129) K Fukamachi and N. Ishibashi, BunsekiKagaku, 26, 69 (1977) (Jpn.). (130) K. Garbett, Proc. Anal. Div. Chem. Soc., 12, 60 (1975). (131) C. Gavach, P. Seta and B. D'Epenoux, J , Hectroanal. Chem., 83, 225

',.

11977) \ , "

(132) R. Geyer and P. Stein, Wiss. Z. Tech. Hochsch. "Carl Schorlemmer", Leuna-Mersburg, 17, 364 (1975). (133) T. J. Gilligan, E. L. Cussler, and D. F. Evans, Biochim. Biophys. Acta. 497. 627 11977). (134) V. N. Goiubev, N. K. Evseeva, I. N. Kremenskaya, and S. K. Timofeeva, Elektokhimiya, 12, 263 (1976) (Russ.). (135) A. V. Gordievskii, A. F. Zhukov, V. V. Snakin, Y. I . Urusov, and V. S. Shterman, U . S . S . R . Patent 486266, Sep. 30. 1975; Appl. 1896716, Mar. 22, 1973; Chem. Abstr., 84. 38365v (1976). (136) A. V. Gordievskii, A. V. Vishnyakov, A. F. Zhukov, V. S. Shterman, and Y. I. Urusov, U.S.S.R. Patent 493721, Nov. 30, 1975; Appl. 2004519, Mar. 13, 1974; Chem. Abstr., 85. 13468p (1976). (137) A. V . Gordievskii, Y. 1. Urusov, A. Y. Syrchenkov, V. V. Sergievskii, A. F. Zhukov, and A. M. Pokidyshev, U.S.S.R. Patent 495597, Dec. 15, 1975; Appl. 2038410, Jun. 28, 1974. (138) L. Gorton and U. Fiedler, Anal. Chim. Acta, 90, 233 (1977). (139) T. Gotow, M. Ohba, and T. Tomita, I€€€Trans. Biomed. Eng., 24, 366 (1977). (140) D. N. Gray and G. G. Guilbault, U.S. Patent 3929609, Dec. 30, 1975; Appl. 328360, Jan. 31, 1973. (141) D. N. Gray and C. C. Young, Brit. Patent 1425912, Feb. 25, 1976: Appl. 26859/74. Jun. 18, 1974. (142) A. Grekovich. E. A. Materova, S. E. Didina. and S. N. Silin, Elektrokhimiya. 12, 723 (1976) (Russ.). (143) M. Gueggi, U. Fiedler. E. Pretsch, and W. Simon. Anal. Let?., 8, 857 (1975). (144) M. Gueggi, M. Oehme, E. Pretsch, and W. Simon, Helv. Chlm. Acta, 59, 2417 (1976). (145) M. Gueggi, E. Pretsch, and W. Simon, Anal. Chim Acta, 91. 107 (1977).

ANALYTICAL CHEMISTRY, VOL. 50, NO. 5, APRIL 1 9 7 8 (146) M. 1. Gugeshashvili, M. A. Manvelyan, and G. L. Neugodova, Tezisy Dokl.-Vses. Soveshch. Nektrokhim., 5th 1974, Pub. 1975, 1, 154: Chem. Abstr., 209649b (Russ.). (147) G. G. Guiibault and T. Cserfalvi, Anal. Lett., 9, 277 (1976). (148) C. Guillot, D. Vanuxem, and C. Grimaud, Pathol. Biol., 24, 431 (1976). (149) J. Gulens and B. Labbate, At. Energy Can. Ltd., (Rept.) AECL-5542 (1976). (150) R. Gvenae, K. Toth. E. Koros. and E. Punaor. M a_. w . Kem. f o l v . , 83. 135 ( 1 9 j 7 ) ?Hung.). (151) I.Haiduc, S. Beicu, and C. Liteanu, Rev. Roum. Chim., 22, 427 (1977). (152) I. Haiduc, D. C. Cormos, and M. Mandrea, Stud. Univ. Babes-Bolyai, Ser. Chem.. 21. 56 (19761 (Rom.1. (153) J. E. Hall and R. Latorre,' Blophys, J . , 16, 99 (1976). (154) A. C. Hansen, K. Engle, P. Kildeberg, and S. Wamberg, Clin. Chim. Acta, 79, 507 (1977). (155) E. H. Hansen, J. Ruzicka, and N. R. Larsen, Anal. Chim. Acta, 79, 1 (1975). (156) C. Harzdorf and H. Keim. Fresenius' Z . Anal. Chem., 279, 263 (1976) (Ger.). (157) S. S. M. Hassan, Mlkrochim. Acta, 1, 405 (1977). (158) N. Hazamoto, N. Kamo, and Y. Kobatake, J . Assoc. Offlc. Anal. Chem., 59, 1097 (1976). (159) T. W. Heaty, D. E. Yates, L. R. White, and D. Chan, J. Electroanal. Chem., 80, 57 (1977). (160) G. J: M. Heijne, W. E. Van der Linden, and G. Den Boef, Anal. Chim. Acta, 89, 287 (1977). (161) G. J. M. Heijne and W. E. Van der Linden, Anal. Chim. Acta. 93, 99 11977). (162) R. W.Hendler, D. Songco, and T. R. Clem, Anal. Chem., 49, 1908 (1977). (163) R. W. Hendler, Anal. Chem.. 49, 1914 (1977). (164) N. C. Hebert, Adv. Exp. Med. Biol., 50 (Ion Sei. Microelectrodes) 23-38 (1974). (165) K. Hiiro. G. J. Moody, and J. D. R. Thomas, Talanta, 22, 918 (1975). (166) W. A. Hildebrandt and K. H. Pool, Talanfa. 23, 469 (1976). (167) R. F. Hirsch and G. M. Olderman. Anal. Chem.. 48. 771 (1976). (168) A. D. Hirst, P. Gay, P. Richardson, and P. J. N. Howorth, Natl. Bur. Stand. ( U . S ) Spec. Pub/., 450, 311 (1977). (169) C. E. HjemdahCMonsen, D. S. Papastathopoulos, and G. A. Rechnitz, Anal. Chlm. Acta. 88. 253 119771. (170) M. Hofton, Environ'. Sci.' Techno/., 10, 277 (1976). (171) E. HoDirtean, M. Chereches. and C. Liteanu. Chem. Anal. (Warsaw), 20, 965 (1975) (172) E Hopirtean, M Jurat, and A I Masa, Rev Chim (Bucharest),26, 872 (1975) fRom I (173) E.'Hopirtean, C. Liteanu, and F. Kormos, Rev. Chim. (Bucharest),28, 378 (1977) (Rorn.). (174) E. Hopirtean, C. Liteanu, and R. Vlad, Talanfa, 22, 912 (1975). (175) E. Hopirtean, M. Preda, and C. Liteanu, Chem. Anal. (Warsaw), 21, 861 (1976). (176) E. Hopirtean, M. Preda, and C. Liteanu, Fresenius' Z. Anal. Chem., 286, 65 (1977). (177) E. Hopirtean and E. Stefaniga, Rev. Roum. Chim., 20, 863 (1975). (178) E. Hopirtean and E. Stefaniga, Rev. Roum. Chim., 21, 305 (1976). (179) E. Hopirtean, E. Stefaniga, and C. Liteanu, Chem. Anal. (Warsaw),21, 867 (1976). (180) E. Hopirtean, E. Stefaniga, C. Liteanu, and I. Guan, Rev. Chim. (Bucharest), 27, 346 (1976) (Rom.). (181) J. E. Horner and C. R. Selby, U.S. Patent 3959 107, May 25, 1976; Appl. 477076, Jun. 6, 1974. (182) G. Horvai, K. Toth. and E. Pungor, Anal. Chim. Acta, 82, 45 (1976). (183) C. P. Hsiung, S. S. Kuan, and G. G. Guilbault, Anal. Chim. Acta. 90, 45 (1977). (184) A. Hulanicki and 2. Augustowska, Anal. Chim. Acta. 78, 261 (1975). (185) A. Hulanicki and A. Lewenstam, Talanta, 23, 661 (1976). (186) A. Hulanicki and A. Lewenstam, Talanfa, 24, 171 (1977). (187) A. Hulanicki. M. Maj-Zurawska, and M. Trojanowicz, Zh. Anal. Khim.. 32, 767 (1977) (Russ.). (188) A. Hulanicki and M. Trojanowicz, Anal. Chim. Acta, 87, 411 (1976). (189) A. Hulanicki. M. Trojanowicz, and M. Cichy, Talanta, 23, 47 (1976). (190) J. 0. Isard, Phys. Chem. Glasses, 17, 1 (1976). (191) IUPAC Analytical Chemistry D on, Pure Appl. Chem., 48. 127 (1976). (192) A. M. Y. Jaber, G. J. Moody, and J. D. R. Thomas, Analyst(London) 101, 179 (1976). (193) A. M. Y. Jaber, G. J. Moody, and J. D. R. Thomas Proc. Anal. Div. Chem. S O C . , 11, 328 (1976). (194) A. M. Y. Jaber, G. J. Moody, and J. D. R. Thomas, J. Inorg. Nucl. Chem., 39, 1689 (1977). (195) J. S. Jacobson and L. I . Helier, J . Assoc. Offic. Anal. Chem., 58, 1129 (1975). (196) J. A. Janata and J. Janata, U S . Patent 3 966 560, Jun. 29, 1976; Appl. 506464, Sept. 16, 1974. (197) J. Janata and S. D. Moss, Biorned. Eng., 11, 241 (1976). (198) 1. Janczarski, E. Lubaszka, and S. Grabiec, Chem. Anal. (Warsaw), 20, 641 (1975) (Pol.). (199) R. H. Jefferson and S. E. Khalafalla, U . S . Bur. Mines, Rep. Invest., R I 8200 (1976). (200) P. Jerrold-Jones and I . H. Krull, U.S.Patent 4012308, Mar. 15, 1977; Appl. 629833, Nov. 7, 1975. (201) A. Jyo, K. Fukamachi, W. Koga, and N. Ishibashi, Bull. Chem. SOC.Jpn., 50, 670 (1977). (202) A. Jyo. T. Hashizume, and N. Ishibashi, Anal. Chem., 49, 1868 (1977). (203) A. Jyo, T. Imato, K. Fukamachi, and N. Ishibashi, Chem. Len.. (7), 815 ( 1977). (204) A. Jyo, H. Mihara. and N. Ishibashi, Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 44, 268 (1976) (Eng.). (205) N. Kamo, N. Hazemoto, and Y. Kobatake, Talanta, 24, 111 (1977). (206) B. Karlberg, Talanfa. 22, 1023 (1975).

27R

(207) M. Kataoka and T. Kambara, J . Electroanal. Chem.. 73, 279 (1976). (208) M. Kataoka, M. Shin, and T. Kambara, Talanta, 24, 261 (1977). (209) T. Kawashlma and G. A. Rechnitz, Anal. Chim. Acta, 83, 9 (1976). (210) N. A. Kazaryan, L. N. Bykova, and N. S. Chernova, Zh. Anal. Khim., 31, 334 (1976) (Russ.). (21 1) 0. Kedem, M. Perry, and R. Bloch, Charged React. Po/ym., 4 (Charged Gels Membr. Part 2), 125 (1976). (212) L. Keil, G. J. Moody, and J. D. R, Thomas, Analyst(London),102, 274 (1977). (213) R. G. Kelly, Electrochim. Acta, 22, 1 (1977). (214) A. S. Keretchuk and N. V. Mokhnatova, Zh. Neorg. Khim., 21, 1195 (1976) (Russ.). (215) M. Kessler, L. C. Clark, D. W. Lubbers, I . A. Silver, and W. Simon, Ed., "Ion and Enzyme Electrodes in Biology and Medicine", Urban and Schwarzenberg or Univ. Park Press, Maryland, (1976). (216) M. Kessler. K. Hajek, and W. Simon, Ref. 215, p 136. (217) C. Kiang, S. S. Kuan, and G. G. Guilbault, Anal. Chim. Acta, 80, 209 (1975). (218) G. 0 . Kim, A. G. Li, and S. N. Kim, PunsokHwahak, 13, 51 (1975); Chem. Abstr., 84, 38307c (1976). (219) G. 0. Kim, A. G. LI, and S. N. Kim, Choson Minjujuuihmin, 23, 148 (1975); Chem. Abstr.. 84. 8 3 6 4 2 ~119761. (220) G. 0. Kim, A. G. Li, and S. N. Kim, ChosonMinjujuuiInmin, 24, 216 (1976); Chem. Abstr., 87, 1536% (1977). (221) G. 0. Kim, A. G. Li, and S. N. Kim, Punsok Hwahak, 14, 108 (1976); Chem. Abstr., 86, 1823759 (1977). (222) K. Kimura and H. Yukio, German Patent, Feb. 17, 1977; Japan Appl. 75/9 Auo 1975: Chem. Abstr.. 86 1 3 5 6 0 3 ~(1977). (223) -N. N. L. Kirsch and W. Simon, Helv: Chim. 'Acta, 59, 357 (1976) (Ger.). (224) S. J. Kirchner and Q. Fernando, Anal. Chem., 49, 1636 (1977). (225) P. Kivalo. R. Virtanen, K. Wickstrom, M. Wilson, E. Pungor, K. Toth, and G. Sundholm, Anal. Chim. Acta, 87. 387 (1976). (226) P. Kivalo. R. Virtanen,. K. Wickstrom. M. Wilson, E. Pungor, G. Horvai, and K. Toth. Anal. Chim. Acta, 87, 401 (1976). (227) H. A. Klasens and J. Goossen, Anal. Chim. Acta, 88, 41 (1977). (228) R. K. Kobos and G. A. Rechnitz, Arch. Bbchem. Bbphys., 175. 11 (1976). (229) R. K . Kobos and G. A . Rechnitz, Biochem. Biophys. Res. Commun., 71, 762 (1976). (230) T. Kojima, Y. Seo, and J. Sato, BunsekiKagaku, 24, 772 (1975) (Jpn.). (231) J. Kontoyannakos, G. J. Moody, and J. D. R Thomas, Anal. Chim. Acta, 85, 47 (1976). (232) J. Koryta, Anal. Chim. Acta, 91, 1 (1977). (233) A. E. Kosov, P. D. Novikov, 0. T. Krylov. and M. P. Nesterova, 0keanologj.a (Moscow), 16, 815 (1976) (Russ.). (234) H. Kotani, T. Kunifusa. and K. Sasaki. German Patent 2 544 360, Apr. 8, 1976; Jpn. Appl. 741114970, Oct. 4, 1974. (235) V. A. Kovda, E. A. Materova, G. K. Zykina, V. V. Snakin. T. L. Bystritskaya, and A. N. Tyuryukanov, Dokl. Akad. Nauk SSSR, 235, 198 (1977) (Russ.). (236) R. P. Kraig and C. Nicholson, Science, 194, 725 (1976). (237) W. R. Kraus, D. J. Kelch, and G. A. Jensen, U.S. Patent 4040928, Aug. 9, 1977; Appl. 235 055, Mar. 16, 1972. (238) Y-S Kwon. J-H Kim, and K-C Park, Taehan Hwahak Hoechi, 20, 486 (1976) (Korean). (239) N. Lakahminarayanaiah, Electrochemistry, 5 , 132 (1975). (240) N. Lakshminarayanaiah, "Membrane Electrodes", Academic Press, New York. N.Y.. 1976. (241) 0. H. LeBlanc and W. T. Grubb, Anal. Chem., 48, 1658 (1976). (242) D. Lerche, J . Membr. Biol.. 27, 193 (1976). (243) J. B. Lesourd and Y. Doucet, J . Chim. Phys. Phys-Chim. Biol., 73, 363 (1976). (244) S. B. Lewis and R. P. Buck, Anal. Led., 9, 439 (1976). (245) J. Licis, Lam. PSR Zinat. Akad. Vestis, Kim. Ser., ( 4 ) ,476 (1976) (Russ.). (246) J. Licis, Lafv PSR Zinat. Akad. Vestis, Kim. Ser., (3), 357 (1977) (Russ.). (247) C. Liteanu, H. Nascu, and I.C. Popescu, Rom. Patent 57418, July 10, 1974; Appl. 67067, May 28, 1971. (248) A. L. Linch, Health Lab. Sci., 12, 182 (1975). (249) E. Lindner, K. Toth, and E. Pungor, Anal. Chem., 48, 1071 (1976). (250) C. Liteanu, E. Hopirtean, and I.C. Popescu, Anal. Chem.,48, 2013 (1976). (251) C. Liteanu, E. Hopirtean, and I. C. Popescu, Anal. Chem.,48. 2010 (1976). (252) C. Liteanu, E. Hopirtean, and E. Stefaniga, Rev. Roum. Chim., 22, 653 (1977). (253) C. Luca and G. Semenescu, Rev. Chim. (Bucharest),26, 946 (1975) (Rorn.). (254) C. Luca, M. Pleniceanu. and N. Muresan, Rev. Chim. (Bucharest),27, 1088 (1976) (Rom.). (255) 0. 0. Lyalin and M. S. Turaeva, Zh. Anal. Khim., 31, 1879 (1976) (Russ.). (256) 0. 0. Lyalin and M. S. Turaeva, Elektrokhimiya, 13, 256 (1977) (Russ.). (257) R. A. Mackay. C. Hermansky. and R. Agarwal. Collodlnfedace Sci, (Frcc. Int. Conf.), 2, 289 (1976). (258) R. A. Macur, 0. H. LeBlanc, Jr., and W. T. Grubb, U S. Patent 3 905 889, Sep. 16, 1975; Appl. 519798, Nov. 1, 1974. (259) V. V. Malev, Elektrokhimiya, 12, 710 (1976) (Russ.). (260) W. U.Malik, S. K. Srivastava, P. Razdan, and S. Kumar, J . Nectroanal. Chem., 72, 111 (1976). (261) H. Malissa, M. Grasserbauer, E. Pungor, K. Toth, M. K. Papay, and L. Polos, Anal. Chim. Acta, 80, 223 (1975). (262) M. A. Manvelvan. G. L. Neuoodova. and L. I. Boauslavskii. Eiektrokbimiva. 12, 1250 ( i m j (RUSS.). (263) H. J. Marsoner and K. Harnoncourt, Aerzfl. Lab., 23, 327 (1977) (Ger.). (264) M. Mascini and T. Muratori, Ann. Chim. (Rome), 65, 287 (1975). (265) E. A . Materova, 2. S. Alagova, and T V. Ryzhkova, Elektrokhimiya. 12, 147 (1976) (Russ.). (266) E. A. Materova. A. L. Grekovich. and N. V. Garbuzova, fonnyi Obmen Ionometriya, 1, 137 (1976) (Russ.). (267) E. A. Materova and V. V. Mukhovikov. Ionnyi Obmen Ionometriya. 1, 106 (1976) (Russ.).

-

28R


(268) E. A. Materova and S. A. Ovchinnikova, Zh. Anal. Khim., 32, 331 (1977) (Russ.). (269) A. Matsubara and K. Nomura, Mem. Fac. Sci. Kyushu Univ., Ser. C. I O , 37 (1976). (270) T. Matsuo, Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 43, 484 (1975) (Jpn.). (271) R. Mauger, J. Chopin-Dumas, and J. C. Pariaud, J . Electroanal. Chem., 83, 251 (1977). (272) C. McCallum and R. Paterson, J . Chem. SOC.,Faraday Trans. 1 , 72. 323 (1976). (273) J. Mertens, P. Van den Winkel, and D. L. Massart, Anal. Chem., 48,272 (1976). (274) M. Meyerhoff and G. A. Rechnitz, Anai. Chim. Acta, 85, 277 (1976). (275) M. Meyerhoff and G. A. Rechnitz, Science, 195, 494 (1977) (276) A. G. A. Merks, Neth. J . Sea Res., 9, 371 (1975). (277) D. Midgley, Anal. Chim. Acta, 87, 7 (1976). (278) D. Midgley. Anal. Chlm. Acta, 87, 19 (1976). (279) D. Midgley, Anal. Chem., 49, 1211 (1977). (280) W. Moelier and 0. Stamm, U.S. Patent 3973555, Aug. 10, 1976; Appl. Swiss 73114659, Oct. 16, 1973. (281) M. S. Mohan ana R. G. Bates, Natl. Bur. Stand. ( U . S . )Spec. Pubi., 450, 293 (1977). (282) G. J. Moody and J. D. R. Thomas, "Invo. Bic-Inorg. Chem.", D. R Williams, Ed. Thomas, Springfield, Ill., (1976) p 220. (283) G. J. Moody and J. D. R. Thomas, Analyst (London), 100, 609 (1975). (284) G. J. Moody and J. D. R. Thomas, J . Sci. Food Agric., 27, 43 (1976). (285) W. E. Morf, Anal. Lett., I O , 87 (1977). (286) W. E. Mod, M. Oehme, and W. Simon, "Ionic Actions Vasc. Smooth Muscle Spec. Regard Brain Vessels, (Symp.), 2nd 1976", E. Betz, Ed., Springer, New York, N.Y. (287) W. E. Morf and W. Simon, Ref. 215, p 51. (288) W. E. Morf, P. Wuhrmann, and W. Simon, Anal. Chem., 48, 1031 (1976). (289) G. P. Morie, Beitr. Tabakforsch., 9, 19 (1977). (290) S. D. Moss, J. Janata, and C. C. Johnson, Anal. Chem., 47, 2238 (1975). (291) M. Muratsugu, N. Kamo, K. Kurihara, and Y . Kobatake, Biocbim. Biophys. Acta, 484, 613 (1977). (292) T. Mussini, Chim. Ind. (Milan), 58, 179 (1976) (Ital.). (293) Nanking Soil Laboratory, K ' o Hseuh Shih Yen, (10) 36 (1976); Chem. Abstr., 86. 182331q (1977). (294) A. Napoli and M. Mascini. Anal. Chim. Acta, 89, 209 (1977). (295) M. Naray, Munkavedekm. 21, 31 (1975) (Hung.); Chem. Abstr., 84 1471081 (1976). (296) Natl. Bur. Stand. ( U . S )Spec. hrbl., 450, U.S. Printing Office, Washington, D.C. 1977. (297) D. P. Newman, U.S. Patent 3979274, Sep. 7, 1976:Appl. 616326, Sep. 34. , 1976 . . -. (298) L. W. Nledrach and 0 . H. LeBlanc, Jr.. U.S. Patent 3 91 1 901, Oct. 14, 1975; Appl. 491 771, Jui. 24, 1974. (299) L. W. Niedrach and W. H. Stoddard. U.S. Patent 3 923 627, Dec. 2. 1975; Appl. 519797, Nov. 1. 1974. (300) H. J. I Nieisen and E. H. Hansen, German Patent 2 652 703, May 26, 1977; Appl. 7515217 Nov. 20, 1975. (301) 8. P. Nikolskii and E. A. Materova, Vest. Leningrad Univ. Fiz. Khim., ( 4 ) 84 (1975) (Russ.). (302) E. P. Nikolskii, E. A. Materova, and A. L. Grekovich, Zh. Anai. Khim., 30, 2223 (1975) (Russ.). (303) T. Nomura and G. Nakagawa, Anal. Lett., 8, 873 (1975). (304) M. Novkirishka and R. Khristova, Anal. Chim. Acta, 78, 63 (1975). (305) M. Oehme, M. Kessler and W. Simon, Chimia, 30, 204 (1976). (306) M. Oehme and W. Simon, Anal. Cbim. Acta, 86, 21 (1976). (307) G. E. Oglesby, W. C. Duer, and F. J. Miiiero, Anal. Chem.. 49, 877 (1977). (308) S. Okazaki, Kagaku (Kyoto), 31, 839 (1976) (Jpn.). (309) V. K. Olson, J. D. Carr, R. D. Hargens, and R. K. Force, Anal. Cbem., 48, 1228 (1976). 1310) H.F. Osswald. R. E. Dohner. T. Meier. P. C. Meier. and W. Simon, Cbimk.

-

.

-

1

(31 1) S. A. Ovchinnikova, E. A. Materova, and V. S. Karavan, Vest. Leningrad Univ., Fiz., Khim., (2) 117 (1977) (Russ.). (312) S. J. Pace and M. J. D. Brand, Natl. Bur. Stand. ( U . S . )450, 227 (1977). (313) D. S. Papastathopoulos and G. A. Rechnitz. Anal. Chim. Acta, 79, 17 ( 197 5). (314) D. S. Papastathopoulos and G. A. Rechnitz, Anal. Chem.. 46, 862 (1976). (315) N. Parthasarathy, J. Buffle, and W. Haerdi, Anal. Chim. Acta, 93, 121 (1977). (316) L. Pataki, K. Harka, J. Havas, and G. Keomley, Radiochem. Radmanai. Lett., 24, 305 (1976). (317) L.Pataki, K. Harka, J. Havas, and G. Keomley, Radiochem. Radioanal. Lett., 25. 205 (1976). (318) L. Pataki, K. Harka. J. Havas, and G. Keomley, Radiochem. Radioanal. Left., 26, 223 (1976). (319) L. Pataki. K. Harka, J. Havas, and G. Keomiey, Radiochem. Radioanal. Lett., 27, 287 (1976). (320) L. Pataki, K. Harka. J. Havas. and G. Keomley, Radiochem. Radioanal. ' Lett., 27, 385 (1976). (321) M. Perry, E. Lobel, and R. Bloch, J . Memb. Sci., I,223 (1976). (322) J. Petranek and 0. Ryba, Czech Patent 165835, Nov. 15, 1976: Appl. 7215529. Aua. 8. 1972. (323) J. Pick, Qung. Sci. Instrum., 34, 41 (1975). (324) G. Popa, G. Birsen, and C. Luca, Rev. Chim. (Bucharest), 26, 512 (1975) (Rom.). (325) J. Prat, Tec. Lab.. 41, 218 (1975) (Span.). (326) J. Prat, TeC. Lab.. 42, 254 (1975) (Span.). (327) J. Prat, Tec. Lab., 43, 308 (1975) (Span.). (328) J. Prat, Tec. Lab., 44, 346 (1975) (Span.). (329) E. Pungor, K . Toth, Z. Feher, G. Nagy, and M. Varadi, Anal. Lett.. 8. ix-xxiii (1975).

(330) E. Pungor, K. Toth, and G. Nagy, Hung. Sci. Instrum., 35, 1 (1975). (331) E. Pungor, K. Toth, and G. Nagy, Ref 215, p 56. (332) E. Pungor, Ed., "Ion-Selective Electrodes", Proc. Matrafurec Conference, Oct. 18-21, 1976, Akademiai Kiado, Budapest (1977). (333) W. Pusch, Chem.-Ing.-Tech., 47, 914 (1975) (Ger.). (334) A. R. Rajput, M. Kataoka, and T. Kambara, J , Electroanal. Chem., 66, 67 (1975). (335) D. Ravaine, M. Audier. and J. L. Souquet, J . Chim. Phys. Phys-Chim. Biol.. 73, 75 (1976) (Fr.) (336) G. A. Rechnitz, G. J, Nogle, M. R . Bellinger, and H, Lees, Clin. Chim. Acta, 76, 295 (1977). (337) A. G. Revesz, Thin SolidFilms, 41, L43 (1977). 1338) G. K. Rice and R. J. Jasinski, Natl. Bur. Stand(U.S.) Spec. Pubi.. 422. 899 (1976). (339) T. L. Riechel and G. A. Rechnitz, Biochem. 6 l o ~ Res. h ~ Commun., ~ 74, 1377 (1977). (340) 7 1972 J H Riseman. U S . Patent 3910607, Oct 7, 1975; Appl. 224 145, Feb.

k

(341) J: Riseman and M. Frant, U S Patent 3984988. Jun 22, 1976; Appl. 218881. Jan 19. 1972 (342) C. J. Rix, A. M. Bond, and J. D. Smith, Anal. Chem.. 48, 1236 (1976). (343) P. A. Rock. T. L. Eyrich, and S. Styer, J . Electrochem. SOC., 124, 530 (1977). (344) H. M. Rohr, Adv. Instrum., 31, Pt. 3, 737 (1976). (345) H. Rottenberg, J . Bioenerg., 7, 61 (1975). (346) T. H. Ryan and E. Fleet, Proc. Anal. Div. Chem. Soc., 12, 53 (1975). (347) D. E. Ryan and M. T. Cheung. Ana/. Chim. Acta, 82, 409 (1976). (348) 0. Ryba and J. Petranek, J . Electroanal. Chem., 67, 321 (1976). (349) E. P. Scheide and R. A. Durst, Anal. Lett., IO, 55 (1977). (350) J. F. Schenck, J . Colloid Interface Sci., 61, 569 (1977). (351) J. G. Schindier and W. Riemann, German Patent 2503 176, Jul. 29, 1976; Appl. Jan. 27, 1975. (352) H. D. Schwartz. Clin. Chim. Acta, 64, 227 (1975). (353) H. D. Schwartz, Clin. Chem. (Winston-Salem), N.C.), 22, 461 (1976). (354) H. D. Schwartz, Clln. Chem. (Winston-Salem, N.C.). 23, 610 (1977). (355) G. Scibona, C. Fabiani, B. Scuppa, and P. R. Danesi, Biophys. J . , 16, 691 (1976). (356) G. Scibona, M. Magini, E. Scuppa, A. Castagnola, and C. Fabiani, Anal. Cbem., 49, 212 (1977). (357) G. E. Secor, G. M. McDonald, and R. M. McCready, J . Assoc. Office Anal. Chem., 59, 761 (1976). (358) I. Sekerka and J. F. Lechner, J . Electroanal. Chem.. 69, 339 (1976). (359) I. Sekerka and J. F. Lechner, Anal. Lett., 9, 1099 (1976). (360) 1. Sekerka, J. F. Lechner. and L. Harrison, J. Assoc. Offic. Anal. Chem., 60, 625 (1977). (361) W. Seiig. Microchem. J . , 22, 1 (1977). (362) M. Semler and H. Adametzova, Chem. Prum.. 25. 377 (1975) (Czech.); Chem. Abstr.. 84. 11802v 11976). (363) M. Sharp, A m i . Chim'. Acta,'85, 17 (1976). (364) A. Shatkay, Anal. Chem., 48, 1039 (1976). (365) G. M. Shean, J . Membr. Sci., 2. 133 (1977). (366) H. Shechter and N. W e n e r , J . Am. Water Works Assoc., 68, 543 (1976). (367) S Sherken, J . Assoc. Offic. Anal. Chem., 59, 971 (1976). (368) N. Shibata, Anal. Chim. Acta, 83. 371 (1976). (369) M. S. Shikanova, M. D. Pukshanskii, A. G. Rodichev, A. G. Sirota, V. G. Krunchak, and G. F. Karkozova, U.S.S.R. Patent 515060, May 25, 1976; Appi. 2083476, Dec. 16, 1974. (370) M. M. Shults and 0. K. Stefanova, Vestn. Leningrad Univ.. Fiz. Khim.. ( I ) , 88 (1976) (Russ.). (371) M. Shuman and W. W. Fogleman. U . S . NTIS, PBRep. 1976, PE254834. (372) W. Simon, W. E. Morf. E. Pretsch, and P. Wuhrmann, "Calcium Transp. Contract. Secretion, Proc. Int. Symp. 1975", E. Carafoli, F. Ciementi, and W. Drabikowski, Ed., North-Holland Pub., Amsterdam. (373) W. Simon, E. Pretsch, D. Ammann, W. E. Morf, M. Gueggi, R. Bissig, and M. Kessler, Pure Appl. Chem., 44, 613 (1975). (374) L. Singer and R. H. Ophaug, Anal. Chem., 49, 38 (1977). (375) K. Soilner, ChargedReact. Symp. 1976, 3 (Charged Gels Membr., Part 11, 3. (376) E. V. Stamicarbon, French Patent 2243626, Apr. 4, 1975; Appl. 73/32 134, Sep. 6, 1973. (377) J. Sternberg, S. J. Updike, and D. P. Lehane, Microtech. Clin. Lab., 1976, 129. (378) F. S. Stover and R. P. Buck, Biophys. J . , 16, 753 (1976). (379) F. S. Stover and R. P. Buck, J . Phys. Chem.. 81. 2105 (1977). 1380) M. Suaawara. T. Nakaiima, and T. Kambara, J , Nectroanal. Chem., 67, ' 315 (1975), (381) J. L Swartz, Adv. Insfrum., 30, Part 2, 608 (1975). (382) W. Szczpaniak, J. Malicka, and K. Ren, Chem. Anal. (Warsaw). 20, 1141 (1975). (383) W.' Szczepaniak, K. Ren, and A. Mickiewicz, Anal. Chim. Acta, 82, 37 (1976). (384) E. L. Szonntagh. U.S. Patent 4 0 3 1 606, Jun. 28, 1977; Appl. 552 284, Feb. 24, 1975. (385) 0. G. Takaishvili. E. P. Motsoneldze, Y. M. Karachentseva,and P. 1. Lavitaya, Zh. Anal. Khim.. 30, 1629 (1975) (Russ.). (386) 0. G. Takaishvili, E. P.Motsoneldze, Y . M. Karachentseva,and P. I. Davitaya, €lekfrokhimiya, 12, 291 (1978) (Russ.). (387) S. Tanikawa, T. Adachi, N. Shiraishi, G. Nakagawa, and K. Kodama, Bunsekl Kagaku, 25, 646 (1976) (Jpn.). (388) S Tanikawa, H. Kirihara, N. Shiraishi. G. Nakagawa, and K. Kodama, Anal. Lett., 8, 879 (1975). (389) J. Tenygl, "Int. Rev. Sci.: Phys. Chem.. Ser. Two 1976", 13, 1. A.D. Buckingham, Ed., Butterworth. London. (390) A. P. Thorna, A. Vlviani-Nauer, S. Arvanitis, W. E. Morf, and W. Simon, Anal. Cbem.. 49, 1567 (1977).

ANALYTICAL CHEMISTRY, VOL. 50, NO. 5, APRIL 1978 (391) J. D. R. Thomas, Proc. Anal. Div. Chem. Soc., 14, 7 (1977). (392) J. D. R. Thomas and G. J. Moody, Proc. Anal. Div. Chem. SOC., 12, 48 (1975). (393) R. C. Thomas, W. Simon and M. Cehme, Nature (London), 258, 754 (1975). (394) D. E. Thompson and R. S. Danchik, Anal. Lett., 8, 699 (1975). (395) S. L. Tong and G. A. Rechnitz, Anal. Lett., 9, 1 (1976). (396) K. Toth, G. Nagy, Z. Feher, and E. Pungor. Fresenius’ 2. Anal. Chem., 282, 379 (1976). (397) K. Toth and E. Pungor, A m . Lab., 8, 9 (1976). (398) I.Trachtenberg, Traces Heavy Met. Water Removal Processes Monit., Proc. Symp. 1973, J. E. Sabadell. Ed., NTIS, Springfield, Va. p 323. (399) K. T. Tran, Tap ChiHoa Hoc, 14, 25 (1976) (Vietnamese); Chem. Abstr., 86, 199369f (1977). (400) T. Treasure and D. M. Band, J . Med. Eng. Techno/.. 1. 271 (1977). (401) P. K. C. Tseng and W. F. Gutknecht, Anal. Lett., 9, 795 (1976). (402) P. K. C. Tseng and W. F. Gutknecht, Anal. Chern., 48, 1996 (1976). (403) A-M. Tsou, K-H. Chang, and H-C. Wang, Hua Hsueh Tung Pao(5), 299 (1976) (Ch.); Chem. Abstr., 86, 164721n (1977). (404) M. S. Turaeva and 0. 0. Lyalin, U.S.S.R. Patent 544899, Jan. 30, 1977; Appl. 1 9 5 0 247, Aug. 3, 1973. (405) Y. I. Urusov, V. V. Sergievskii, A. Y. Syrchenkov, A. F. Zhukov, and A. V. Gordievskii, Zh. Anal. Khim., 30, 1757 (1975) (Russ.). (406) J. J. Vallon, Lyon Pharm., 26, 487 (1975) (Fr.). (407) R. E. Van De Leest, Analyst (London). 101, 433 (1976). (408) R. E. Van De Leest, N. M. Beekmans, and L. Heijne, German Patent 2600846, Aug. 19, 1976; Neth. Appl. 75/823, Jan. 24, 1975. (409) R. E. Van De Leest and L. Heijne, German Patent 2621 731, Dec. 9, 1976; Neth. Appl. 7516410, May 30, 1975. (410) M. A. Van den Heede, A. M. Heyndrickx, C. H. Van Peteghem, and W. A. Van Zele, J . Assoc. Offic. Anal. Chem., 58, 1135 (1975). (41 1) P. Van den Winkel, J. Mertens, T. Boel, and J. Vereecken, J , N e c t r o c k m . Soc., 124, 1338 (1977). (412) J. M. Van der Meer, G. Den Boef and W. E. Van der Linden, Anal. Chim. Acta, 79, 27 (1975). (413) J. M. Van der Meer, G. Den Boef, and W. E. Van der Linden, Anal. Chim. Acta. 85. 317 (1976). (414) J. M. Van der Meer and J. C. Smit, Anal. Chim. Acta, 83, 367 (1976).

29R

(415) L. H. J. Van Kempen and F. Kreuzer, Natl. Bur. Stand(U.S.), Spec. Publ., 450, 239 (1977). (416) G. W. S. Van Osch and B. Griepink, Fresenius’ 2.Anal. Chem., 283. 29 (1977). (417) G. W.’S. Van Osch and B. Griepink, Fresenius’ 2 . Anal. Chem., 284, 267 (1977). (418) M. L. Verkhovskaya, E. S. Imasheva, G. A. Kurella, and L. G. Yaglova, Biol. Nauki(Moscow), 19. 142 (1976) (Russ.). (419) J. VeseM and J. Jicdra. Czech Patent 163358, Jun. 15, 1976; Appl. 68/5344 Jul. 22, 1968. (420) Y. G. Vlasov, I. V. Murin and E. A. Bichkov. Vestn. Leningrad Univ., 22, 129 (1975) (Russ.). (421) Y. G. Vlasov, A. L. Grekovich, E. A. Materova, I. V. Murin, and S. B. Kochereain. Ionnvi Obmen Ionometriva. 1. 170 11976) (Russ.). (422) Y. G-Vlasov, ‘S.B. Kocheregin, and’Y. E. Ermolenko, Elekrrokhimiya, 13, 109 (1977) (Eng.). (423) T. B. Warner, Phys. Chem. Sci. Res. Rep. 1975 l(Nat. Seawater, Rep. Dahlern Workshop 1975), 191. (424) B. Watson and P. J. Breno, U S Publ. Pat. Appl. B 51 1002, Mar. 6, 1976; Appl. 511 002, Oct. 1, 1974. (425) R. Wawro and G. A Rechnitz, J . Membr. Sci., 1, 143 (1976). (426) C. C. Westcott, Anal. Chim. Acta, 86, 269 (1976). (427) M. Whitfield, Proc. Anal. Div. Chem. Soc., 12, 56 (1975). (428) R. D. Wyvill, Prod. Finish. (London). 30, 21 (1977). (429) C.C. Young, U S . Patent 4 033 777 Jul. 5, 1977. Appl. 51 1 720, Oct. 3. 1974. (430) J. N. Zemel. Res./Dev., 28, 38 (1977). (431) J. N. Zemel, Anal. Chem., 47, 255A (1975). (432) M. S. Zetter, German Patent 2646314 May 5, 1977; U.S. Appl. 625857, Oct. 28. 1975. 1433) P.-L: Zhu. Hua Hsueh Tuna Pao. 15) 1Ch.l: , , 300 (1975) , , , Chem. Abstr.. ’ 84, 51371p (1976). (434) A. F. Zhukov, A. V. Gordievskii, V. S. Shterman, A. Y. Syrchenkov, and Y. I. Urusov, U.S.S.R. Patent 515984, May 30, 1976; Appl. 1939 127, Jul. 3. 1973. (435) A.F. Zhukov. A. V. Vishnyakov. Y. L. Kharif, Y. I. Urusov, F. K . Volynets, E.I. Ryzhikov, and A. V. Gordievskii, Zh. Anal. Khim., 30, 1761 (1975) (Russ.).

Gel Permeation Chromatography (Steric Exclusion Chromatography) V. F. Gaylor” The Standard Oil Company (Ohio), 4440 Warrensville Road, Cleveland, Ohio 44 128

H. L. James Waters Associates Inc., Maple Street, Milford, Massachusetts 0 1757

This review covers the time period of about December 1975 to November 1977. Since we depend on abstracting services in some cases, there is some time overlap with the period covered by the last review (73). The literature surveyed for this review included major analytical, chromatography, and polymer journals, as well as various abstracting services. We’ve included literature on size separation from soft gels (“gel filtration”), semi-rigid gels (“GPC”), and porous, inorganic column packings (“rigid gels”). And we‘ve reviewed size separations involving small molecules as well as work restricted to macromolecules. We continue to use the common abbreviation, GPC, for gel permeation chromatography applications involving all the above areas. The more definitive “steric exclusion chromatography” is, however, still preferred nomenclature.

GENERAL REVIEWS A number of books published during this period included one or more sections on theory and use of steric exclusion chromatography (28,55,152,174,176).Several review articles also included general GPC information. Abbott ( 1 ) and Miller (129) discussed elementary operating principles and usefullness for polymer analyses. Krauss and Krauss reviewed theory and practice of both thin layer and column GPC (105). Current status of aqueous GPC was reviewed by Cooper and 0003-2700/78/0350-029R$Ol . O O / O

Matzinger (40). Billmeyer reviewed trends in polymer characterization and discussed some of the limitations of GPC (24). A more general review discussed problems in optimizing high performance liquid chromatography (223),and correlations between GPC and affinity chromatography were included in a review of the latter subject (178).

LITERATURE SERVICES Bimonthly fact sheets summarizing current literature on gel permeation chromatography are now available from England (194). Preston Technical Abstracts Company issues monthly abstracts of current liquid chromatography literature (160), and Chemical Abstracts Service added High Speed Liquid Chromatography to the bimonthly CA Selects service (33); both of these series of abstracts include exclusion chromatography. A bibliography of 1971-73 literature on liquid chromatography was published as a supplementary volume to the Journal of Chromatograph3 (54). And a compilation of liquid chromatography data is now available from the American Society for Testing and Materials (8).

APPARATUS A bewildering array of high resolution liquid chromatographs is now marketed. McNair (128)reviewed requirements C 1978 American Chemical Society

Ion selective electrodes - ACS Publications - American Chemical Society

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