Ultraviolet Spectrometry Robert C . Hirt, Central Research Division, American Cyanamid Co., Stamford, Conn. and 1. M . Vandenbelt, Parke, Davis & Co., Ann Arbor, Mich.
T
of fundamental developments in ultraviolet spectrometry is concerned with the period from the last review (48), October 1961 until November 1963. An attempt has been made t o make it selective rather than comprehensive. Gndoubtedly, many good papers on analytical applications of ultraviolet spectrometry have been passed over in the choice of examples. Articles reporting spectra in connection with characterization of compounds, spectrastructure correlations, and use in kinetic studies generally have not been included. Preference has admittedly been given to papers in the English language which are readily available t o the analyst. I t is perhaps an indication of the increasing maturity and sophistication of the field of ultraviolet spectrometry that a n appreciable number of books on the subject have appeared while the number of papers reporting analytical methods and gadgetry have decreased. Simultaneously. the information retrieval aspects have increased greatly with the growth of collections of good quality spectra. To find the published spectra of a particular compound or of related compounds is no longer a difficult and frustrating task. HIS BIENNIAL REVIEW
BOOKS A N D REVIEWS
Ultraviolet spectrophotometry has suffered for years from a lack of adequate texts combining theory and applications. There were books that attempted to cover all or several fields of spectroscopy or analytical chemistry; these were handicapped by lack of space for each area. Potential authors may have hesitated because of the large gap bet\$een theory and the empirical laws and practices of electronic spectroscopy. Fortunately, the various books which have appeared recently have tended rather more to complement each other than to cover only the same material. Some do fall short of their purpose by repeating much of older works. Probably the most significant book to appear during the review period is “Theory and Applications of Cltraviolet Spectroscopy” by Jaffe and Orchin (52). I t is especially successful in bridging the fundamentals of theory and 308 R
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empirical spectra-structure correlations. It is naturally not strong on analytical applications, since it is designed more for the understanding and applications of the organic chemist than the kinetics or quantitative measurements of the analyst. It has been reviewed most favorably (1.4, 29, 70, 74, 75, 116). From England comes “Molecular Spectroscopy: Methods and Applications in Chemistry” by Beaven and coauthors (11). Volume 1 devotes about 160 pages t o ultraviolet and visible spectrometry, reviex ed by Simmons (99). One chapter on electronic Spectra is included in “Introduction to Molecular Spectroscopy” by Barrow ( 7 ) . This has been reviewed (72). “Elementary Introduction to Molecular Spectra” by Bak (6) has appeared in its second edition. One reviewer (81) points out that it is a useful introduction for students or a survey for workers in related fields. “Absorption Spectroscopy” by Bauman ( 9 ) is a practical textbook with a definite theme. It was reviewed favorably (4). “Advances in Spectroscopy, Vol. 11,” edited by Thompson ( l o g ) , included a review of the ultraviolet spectra of proteins and related compounds by Beaven (10): it has been reviewed by Rosenbaum (90). “Developments in Applied Spectroscopy,” (34) edited by Ferraro and Ziomek, constitutes a compilation of papers presented a t a symposium rather than a summary of review. I t has been reviewed (97). An article on the far ultraviolet spectra of steroids is of interest (112). One chapter by White (124) in the “Progress in Nuclear Energy, Series IX” (26) deals with the spectra of certain heavy elements, actinides, and the technique of molten salts as solvents. Headridge (47) summarized photometric titrations. This was reviewed by Malmstadt (69). A small book by Rao (86) treats ultraviolet and visible absorption spectra and fluorescence rather in the style of older testooks. It has been reviewed by Gould (40). A book entitled “Spectrometric Identification of Organic Compounds” (98) is primarily concerned with the powerful identificational tools of infrared, S M R , and mass spectrometries, and includes ultraviolet only as a supplemental technique, with no use of its quantitative
aspects other than intensity ranges. The examples given are of relatively simple molecules, however. I t has been reviewed by Chapman (22). “Practical Pharmaceutical Chemistry-Quantitat h e Analysis” (12) includes ultraviolet methods [revien ed by Stephenson (107)]. d chapter on absorption spectrometrj (2f) is included in “The Science of Surface Coatings” nhich was edited by Chatfield (23). Cooke (25) hab reviewed “Chemical Spectroscopy” by Dodd (28). In a closely related field, “Polarized Light” by Shurcliff (96) is worthy of mention (72). Spectrophotometry using polarized light in some manner will probably become increaiingly important in analytical applications of spectrometry. COLLECTIONS OF SPECTRA A N D INDICES
The Sadtler collection of ultraviolet spectra (91) has grown from 1500 t o 6000 since the last review. Special attention was given the choice of solvent with these spectra, and indices are furnished listing compound names alphabetically and in numerical equence. The American Petroleum Inditute Project 44 has continued to issue spectra; this collection totals 917. The first two volumes of the Lang series have been joined by two more (63). These four volumes contain 170, 179, 172, and 170 spectra, respectively. Each is furnished mith indices giving compounds alphabetically by name, empirical formula, numerical sequence, and alphabetically by contributor. Literature references are included. The first two volumes of “Organic Electronic Spectral Data” (53, 113) have amply proved their value in the la5t two years. Volume IV, edited by Phillips and Nachod (84), is out, covering the literature of 1958 and 1959 in the same manner as the earlier volumes. Volume I11 for 1956-7 should appear shortly. Committee €3-13 on Absorption Spectroscopy of the American Society for Twting and Materials, has continued to isbue International Business Machines punched cards on ultraviolet and visible spectral data. These are summarized in Table I.
.
Table 1. Compositioir of Ultraviolet and Visible Spectral Data Cards (ASTM E-1 3 I B M Cards) 917 A.P.1. 14,447 Literaturi:
1,225 Sadtler 13 1I.C.A.
These decks, and Name-Formula Cards for each entry, can be obtained from L. E. Kuentzel, Wyandotte Chemicals Corp., Wyandotte, Mich. I n addition, h S T M E-13 has issued “CODEN for Periodicd Titles-1963” as STP No. 329 (59). The CODEN system, a four-letter designation for each journal, is used on the NameFormula Cards and also in the Ylolecular Formula Index (ASTM S T P No. 357) (60). This index is a listing, in book form, of molwular formulae, numerical index, nameii of compounds, and references to published ultraviolet and visible spectra for everything in the ASTM Index through the Fifth Supplement. The Molecular Formula Index would be useful to spectroscopists who do not possess the ASTM-IBhI punched cards and sorting equipment, for it can be used as an index t o the literature in the same manner as the indices by Hershenson ( 4 8 ) ) and the volumes of Organic Electronic Spectral Data. Phillips (83) made a study of wavelength and absorption reproducibility, using data on a hundred compounds which were duplicat,ed in Volume I V of “Organic Electronic Spectral Data.’’ Agreement was good on maxima to 2 mw, but many intensities showed a relative error of 25%. It is interesting to note that 2 mp was .;he spectral resolution selected by the Standard Data Subcommittee of ASTM E-I3 over a decade ago for coding ultraviolet spectral data onto punched cards. Hayden et al. (46) coinpiled infrared, ultraviolet, and visible spectra of some reference standards from the U. S. Pharmacopoeia and National Formulary. Copies are availabe from the Association of Official Agricultural Chemists, Box 540, B. Franklin Station, Washington 4, D. C., for $2.00. EQUIPMENT AND ACCESSORIES
Interest in novel absorption cells and accessories and modifications of commercial instruments mttrks a healthy state of affair*. A low temperature cell for use in the study of cytochromes eml)loyed an oval-shaped Dewar flask fitted to the cell comparl ment of a Cary spectrophotometer (52). The measurement of adsorbed species was made by supporting a thin film cln quartz fibers
(64). A split compartment cell was devised (1%) to observe the spectra of two components before and after mixing, and the detection thereby of new species or components such as complexes. ,4 cell for measuremt of t’he reflectance of powders was described ( 6 ) . A new universal spectrophotometer, employing a Beckman DK-1-A and a grating monochromator, was described as suitable for emission, fluorescence, phosphorescence, and polarization studies as well as absorption work (55). Both scanning and nonscanning microspectrophotometers were described (127). Areas down to a square micron can be photographed at various wavelengths by an instrument used by Ragener and Grand (118). A scaling and integrating spectrophotometer (119) has been built to scan very small objects a t wavelengths down to 230 mp. A multipass spectrometer was devised for measurement of the absorption of monomolecular films on water (111).
Resolution in derivative recording of spectra was discussed (102). An improved method for error calculation of quantitative methods was presented ( ~ 0 8 )emphasizing , errors due to intercepts and slopes of calibration curves, and describing errors in * diff erent’ial as well as classical methods. Christensen and Potter (24) presented a geometrical analysis of double monochromator systems, covering double, dual-pass, and tandem monochromators, and the effects of the sizes and positions of slits. Beer’s law reached the slide rule stage, with the construction of a simple device relating absorbance, concentration, and molar absorptivity (15). The interaction between linear-behaving components may cause instability in a multi-component system, causing errors to arise even though Beer’s law is obeyed. This situation is analyzed for a four-component system (133). Automatic or continuous recording, particularly with application to esamination of column fractions, was the central topic of a number of papers. hiarr and Marcus ( 7 1 ) described the modification of a Beckman DU spectrophotometer t o record linearly in absorbance by use of a commercial D C amplifier and a network of silicon diodes. This was used for the assay of enzymes. Two articles by Wood and Gilford (128, 129) were concerned with a similar system, using a cuvette-positioning device, and its application t o the following of enzyme reactions. Anderson ( 2 ) applied a pneumatic wavelength shifter for measurements a t two wavelengths in the analysis of nucleotide derivatives. A continuous analyzer used a Beckman 3700 Flow Colorimeter a t 360 mp to monitor the chlorine released from hot sodium chloride by fluorine (31). A list of solvents suitable for
phosphorimetry was presented (126). These make clear glasses a t low temperatures and would be useful also for absorption studies. King and Hercules (58) pointed out a nonlinearity in grating instruments that could cause a false band of shoulder in fluorescence spectra; this could happen also in a single-beam absorption instrument. This is called Rood’s Anomaly, an irregularity in the transmission or reflection curve with wavelength that sometimes occurs with high-dispersion, blazed gratings. It emphasizes the need for careful calibration work. SCREENS A N D FILTERS
The quest for a good absorbance standard in the ultraviolet has continued. Both screens and filters have staunch advocates. Slavin (100) discussed these as photometric standards. I n another paper (101), he listed the absorption edges of selected compounds for checking the stray light in spectrophotometers, and presented a monograph relating per cent stray light, absorbance value, and photometric error. An investigation of screens as absorbance standards by Vandenbelt (114) indicated that they are not so dependable as appropriate glass filters. The use of wire screens as variable light attenuators was discussed by Bryan (19). Narrow band-pass filters were used (117) in the continuous determination of protein a t 280 mp. Vacuum ultraviolet interference filters were made of deposited aluminum (93). Samarium and neodymium chlorides were used to calibrate the wavelength scales of a spectrophotometer (36). Keegan (56) has incorporated a variety of transition elements in transparent base glasses which shon promise of providing both wavelength and photometric filter standards for the ultraviolet. Hartree (4.5) discussed the need for a standard criterion for stray light in ultraviolet spectrophotometers. VACUUM ULTRAVIOLET SPECTROMETRY
A stream of papers has appeared dealing with spectrometry in the region below 2000 Angstroms. Most of these are concerned with light sources and detectors for instruments which are not of immediate analytical interest but suited to space exploration and simulation. h review of these was put out by Milazzo (73). An extensive “Bibliography of Vacuum Ultraviolet Spectroscopy” was published (49). This contains over 1300 references arranged alphabetically according to senior author and indexed by subject. It can be obtained through the Office of Technical Services, Kashington, 11. C. 20234, under number AD 401 498. VOL. 36, NO. 5, APRIL 1964
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Kaye (64) pointed out that nearly all compounds show strong absorption a t 170 mp, and applied special silica flowthrough cells of 1, 5, and 10 cm. to a Beckman DK-2 for the detection of gas chromatograph effluent. New light sources (87, 150) and detectors (67)were proposed. INORGANIC ANALYSIS
Determination of elements or ions by colorimetric methods naturally extends into the ultraviolet. The reagent 8quinolinol was employed by several authors to form complexes with metals. Eberle (50) used the absorption of tungsten-8-quinolinolate a t 358 mfi to determine tungsten in nuclear material and steel. Tin and molybdenum also were determined in similar materials (51). The 8-quinolinol complex with cobalt absorbs at 365 and 700 mp, while that of nickel absorbs only at the shorter wavelength ( 7 6 ) ; this permits simultaneous analysis of these two elements. Complexes of titanium have been studied (94). Sawicki and coworkers (92) reviewed 52 methods for the determination of nitrite; at least five of these employed absorption in the ultraviolet. The reagent 2,6-xylenol was used for the determination of nitrate down to 2 p.p.m. (44). The strong absorption of nitrate near 210 mp was used directly by Armstrong (5), together with a background correction derived from the absorption a t 275 mp. Nitric oxide in auto exhaust was oxidized with oxygen and measured in 12-inch cells with a Beckman DU spectrophotometer equipped with a recorder (78). No11 and Stefanelli (79) compared the fluorometric and spectrophotometric methods for determination of aluminum; the latter was based on absorption of the complex with 8-quinolinol a t 380 mp. Freedman (37) reported the determination of rhenium in tungsten alloys by a spectrophotometric method. Cobalt and nickel can be determined using bis-cyclohexanone - oxalyl dihydrazone as a reagent (80). Indirect measurement of silicon was effected by using the change in molybdate absorption at 230 mp (110). Chlorine and its oxides may be determined in carbon tetrachloride, as described by Spurny (104). ORGANIC ANALYSIS
As in previous years, perhaps the most common application of ultraviolet spectrometry has been the quantitative measurement of absorbing organic molecules, particularly in low concentration ranges. This section presents a sampling of these important applications. Developments include the use of computers t o solve problems heretofore considered too laborious. A least
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squares treatment was made using an ARMAC computer for determination of the three isomeric toluene-sulfonic acids (20),employing absorbance values a t 39 evenly spaced wavelengths. Because many steroids have spectra differing only in molar absorptivities, an analog computer was employed to obtain plots of ratios of molar absorptivity values a t a fixed wavelength (39). Harris and Zoch (42) used the absorption at 276 mp of furfural complexed with .bisulfite ion as a means of determining furfural in the presence of sulfur dioxide. With an extraction procedure, Gunther and coworkers (41) were able to determine both biphenyl and ophenylphenol present in citrus fruits. The characterization of aromatics from light catalytic cycle stocks was described in two articles (1, 8 ) ; infrared, mass spectrograph, and nuclear magnetic resonance techniques were used in addition to ultraviolet. Decaborane was determined a t 272 mp in cyclohexane (61); this method was described along with other analytical methods, noting t h a t interferences from impurities constitute a major problem. Beaven (10) reviewed the ultraviolet absorption spectra of proteins and related compounds. Advantage was taken of the spectral changes resulting from acetal formation for the determination of aldehydes ( 2 7 ) ; spectra in methanol were compared to those in acidified methanol for 49 aldehydes. The spectroscopic properties and behavior of the acetoxy group were reviewed (116). A color-developed technique, comparing absorbances a t 385 and 435 mp was utilized by Hartford (45) as a rapid analytical method for itaconic, citric, aconitic, and fumaric acids. Determination of trace amounts of benzoic acid in phthalic acid anhydride, a difficult problem, was solved by conversion of the anhydride to the sodium salt and extracting with chloroform using 274 mp as the analytical wavelength (77). A cyclohexane extraction was employed prior t o the determination of aromatics in connection with carbanion oxidations (85). Microgram quantities of divinyl sulfone were determined by measuring the decrease in absorption as benzenethiol reacted with divinyl sulfone in alkaline aqueous solution (106). A similar measurement involving decrease in absorbance was the oxidation of triphenyl phosphine by hydroperoxide, giving a quantitative determination of the latter (106). Spears (103) examined fractions from a chromatographic separation to measure phenol in cigarette smoke. The differences between alkaline and acidic forms were recorded directly on a double beam spectrophotometer to determine phenolic substances (123). Aminobenzoic acid in a mixture of acetic and
phosphoric acids was effective for the determination of sugars (65). Difference spectra a t two p H values were taken to measure milk proteins (125). Sulfuric acid was used as a reagent for determining 20-methylcholanthrene in body tissue; wavelengths of 327 and 292 mp were used (132). Alkylbenzenesulfonates were determined a t 225 mp in a buffered solution designed t o prevent losses by adsorption onto glass vessels (122). BIOLOGICAL A N D PHARMACEUTICAL APPLICATIONS
Ultraviolet spectrometry is often a preferred method for the study of biological systems, and measurement of relevant factors, constituents, and agents. An ultraviolet modification of the biuret reaction was described which is several times more sensitive than the traditional visible procedure (53). Ribonuclease activity was measured by changes in absorption of the baAic dye thionine with depolymerization (95). Cytotoxic agents were separated from other active components and read with ultraviolet (17). One penicillin derivative was differentiated from, and measured in the presence of, other similar forms (120). Drug levels and metabolites were determined in biological tissues and juices after extraction and separation, such as the determination of phenindione (16). Ultraviolet measurements have become of fundamental importance to virtually all phases of pharmaceutical research and development. Applications include drug criteria and standards, determination in various systems and in the presence of extraneous components, stability, kinetics, formulation, and control. Ionization constants were determined on microgram Amounts of material by spectrophotometric absorption (89). Traces of m-aminophenol were measured in p-aminosalicylic acid (68). Phenobarbital and pentobarbital were assayed in mixtures (18). The stability of epinephrine (88) and rate studies of niacinamide hydrolysis (56) were described. A method was developed for analysis of ternary mixtures (82), and the prediction of drug and formulation stabilities from measurements at elevated temperatures was reviewed (58). The factors involved in preparation of clear injectable solutions of Warfarin were examined in one study (60), and the effects of various types of vial closures on seIfsterilizing agents in another (62). MISCELLANEOUS
Kendall and Huke (67) discuss the use of difference spectra for purposes of identification. Lincke and Wilkerson (66) describe a new photoemission-
scintillation detector with a gold cathode. The use of chloroformisopropyl alcohol mixed solvent is described (13) for spectrophotometric titration of some divalent metals. Holt (51) modified the water lines on the hydrogen lamp of a Cary spectrophotoyeter for ease in replacement and realignment. LITERATURE CITED
(1) Aczel, T., Bartz, K. W., Lumpkin, H. E., Stehling, F. C., ANAL. CHEM. 34, 1821 (1962). (2) Anderson, N. G., Anal. Biochem. 4, 269 (1962). (3) Armstrong, F. A. J., ANAL. CHEM. 35, 1292 (1963). (4) Asendorf, R. H., Physics Today 16, No. 3, 62 (1963). (5) Bak, B., “Elementary Introduction to Molecular Spectra,” 2nd Ed., Wiley, Kew York, 1962. (6) Barnes, L., Goya, H., Zeitlin, H., Rev. Sci. Znstr. 34, 292 (1963). (7) Barrow, G. M . , “Introduction to Molecular Spectroscopy,” McGraw-Hill, New York, 1962. (8) Bartz, K. W., Acr:el, T., Lumpkin, H. E., Stehling, F. C., ANAL.CHEM. 34, 1814 (1962). (9) Baumap! R. P., ‘Absorption Spectroscopy, Wiley, S s w York, 1962. (10) Beaven, G. H., “Advances in Spectroscopy”, Vol. 11, Thompson, H . W., ed., pp. 429-472, Interscience, New York, 1961. (11) Beaven, G. H., Johnson, E. A,, Willis, H. A,, Miller, R. G. J., “Molecular Spectroscopy: M e t p d s and Applications in Chemistry, Part I, pp. 3-162, Heywood & Co., London, 1961. (12) Becket, A. H., Stenlake, J. B. “Practical Pharmaceutical ChemistryQuantitative Analysiri,” Athlone Press, London, 1962. (13) Behm, R. K., Robinson, R., ANAL CHEM.35, 1010 (1963). (14) Berry, R. S., Spectrochim. Acta 19, 1699 (1963). (15) Blumer, M., Analf/st 87, 398 (1962). (16) Bose, B. C., Vijztyvargiya, R., J . Pharm. & Pharmacol 14, 58 (1962). (17) Broadsky, T. F., Lummis, W. L., J . Pharmaceu. Sci. Si!, 230 (1963). (18) Brown, T. L., Ibid., 52, 274 (1963). (19) Bryan, F. R., Appl. Spectroscopy 17, 19 (1963). (20) Cerfontain, H., Iluin, H. G. L., Vollhracht, L., ANAL.CHEM.35, 1005 ( 1963). (21) Chapman, D., ‘ T h e Science of Surface Coat>ings,” Chatfield, H . W., ed., Ch. 19, pp. 540-550, Ernest Benn, London, 1962. (22) Chapman, 0. L., J . Am. Chem. SOC.85, 3316 (1963). (23) Chatfield, H. W., “The Science of Surface Coatings, Ernest Benn, London, 1962. (24) Christensen, R. L., Potter, R. J., Appl. Optics 2 1049 (1963). (25) Cooke, W. b.,ASAL. CHEM.35, No. 4, 71A (1963). (26) Crouthamel, C. E., ed., “Progress in Nuclear Energy,” Series IX, “Analytical Chemietry,” Vol. 2, Pergamon Press, New York, 1961. (27) Crowell, E . P., Powell, W. A,, Vamel, C. J., Ibid., 35, 184 (1963). (28) Dodd, R. E., “Chemical Spectroscopy,” Elsevier, New York, 1962. (29) Doub, L., Record C‘hem. Progress 24, No. 3, 193 (1963). (30) Eberle, A. R., A N A L .CHEM.35, 669 (1963). , . ! ?1
(31) Eberle, A. R., Lerner, M. W., Ibid., 34, 627 (1’962). (32) Elliott, W. B., Tanski, W., Zbid., 34, 1672 (1962). (33) Ellman, G. L., Anal. Biochem. 3, 40 (1982). (34) Ferraro, J. R.. Ziomek. J. S.. eds.. ~, “Developments in Applied Spectrosl copy,” Vol. 2, Plenum Press, New York, 1963. (35) Finholt, P., Higuchi, T., J . Pharmaceu. Sci. 51, 655 (1962). (36) Fog, J., Osnes, E., Analyst 87, 760 (1962). (37) Freedman, ,If. L., ANAL.CHEM.34, 865 (1962). (38) Garrett, E. R., J . Pharmaceu. Scz. 51, 811 (1962). (39) Garrett, E. R., Johnson, J . L., Alwav. C. D.. ANAL. CHEM.34. 1472 (1965): (40) Gould, J. H., J . O p t . SOC.Am. 52, 837 (1962). (41) Gunther, F. A., Blinn, R. C., Barkley, J. H., Analyst 88, 36 (1963). (42) Harris. J. F.. Zoch. L. L.. ANAL. ~, CHEM. 34, 201 (i962). ’ (43) Hartford, C. G., Zbid., 34,426 (1962). (44) Hartley, A. M., Asai, R. I., Zbid., 35, 1207 (1963). (45) Hartree, E . F., Photoelectric Spectrometry Group Bull. 15, 398 (1963). (46) Hayden, A. L., Summul, 0. R., Selzer, G. B., Carol, J., J . Assoc. O$. Agr. Chemists 45, 797 (1962). (47) Feadridge, J. B., “Photometric Titrations,” International Series of Monographs on Analytical Chemistry, Vol. 4, Pergamon Press, Oxford, England, 1961. (48) Hirt, R. C., ANAL.CHEM.34, KO. 5, 276R (1962). (49) Hirt, R. C., Schmitt, R. G., “Bibliography of Vacuum Ultraviolet Spectroscopy,” Tech. Doc. Report No. ASD-TDR-62-915 (1963), OTS-AD~
401-498.
(50) Hiskey, C. F., Bullock, E., Whitman, G., J . Pharmaceu. Sci. 51, 43 (1962). (51) Holt, D. H., Appl. Spectroscopy 17, 26 (1963). (52) Jaffe, H. H., Orchin, M., “Theory and Applications of Ultraviolet Spectroscopy,” Wiley, New York, 1962. (53) Kamlet, M . J., ed., “Organic Electronic Spectral Data,” Vol. I, 19461952, Interscience, New York, 1960. (54) Kaye, W., ANAL. CHEM.34, 287 (1962). (55) Kaye, W., Appl. Optics 2, 1295 (1963i. \ - - - - I -
(56) Keegan, H. J., J . Opt. SOC.Am. 53, 517 (1963). (57) Kendall, C. E . , Huke, D. W., Photoelectric Svectrometrv Grouv Bull. 15. 401 (1963): (58) ‘King, R. AI., Hercules, D . AI., ANAL.CHEM.35, 1099 (1963). (59) Kuentzel, L. E., “CODEK for Periodical Titles-1963,’’ A m . SOC. Testing Mater., Spec. Tech. Publ. No. 329 (1963). (60) Kuentzel, L. E., “llolecular ForAm. S o r . mula Index-IJltraviolet.” Testing Mater., Spec. Tech. Pub!. No. 357 (1963). (61) Kuhns, L. J., Braman, R. S., Graham, J. E., ANAL.CHEM.34, 1700 ( 1962). (62). Lachman, L., Weinstein, S.,Hopkms, G., Slack, s.,Eisman, P., Cooper, J., J . Pharmaceu. Sci. 51, 224 (1962). (63) Lang, L., “Absorption Spectra in the Ultraviolet and Visible Region,” Academic Press, Budapest, Hungary, Vol. I1 (1961), Vol. I11 (1962), Vol. IV (1963). (64) Leftin, H . P., Rev. Sci. Instr. 32, 1418 (1961). (65) Leopold, B., ANAL.CHEM.34, 170 (1962.)
(66) Lincke, R., Wilkerson, T. D., Rev. Sci. Znstr. 33, 911 (1962). (67) Lothian, G. F., Analyst 88, 678 (1963). (68) Luers, R. B., Stadler, L. B., J . Pharmceu. Sei. 51, 178 (1962). (69) Malmstadt, H. V., ANAL.CHEM.35, No. 4, 71A (1963). (70) Margrave, J. L., Chem. & Eng. News 41, No. 27, 62 (1963). (71) Marr, A. G., Marcus, L., Anal. Biochem. 2, 576 (1961). (72) May, L., Appl. Spectroscopy 17, 107 (1963). (73) Milaezo, G., Pure & Appl. Chem. 4, 135 (1962). (74) Morgan, K . J., Anal. Chem. Acta 29, 94 (1963). (75) Morton, R. A., Analyst 88, 656 (1963). (76) Mukhedkar, A. J., Deshpande, N. V., ANAL.CHEM.35, 47 (1963). (77) Murnieks, R., Gonter, C. E., Ibid., 34, 197 (1962). (78) Nicksic, S.W., Harkins, J., Ibid., 34, 985 11962). (79) Noll, c. A., Stefanelli, L. J., Zbid., 35, 1914 (1963). (80) Omang, S. H., Selmer-Olsen, A. R., Anal. Chzm. Acta 27. 335 (1962). (81) Overend, J., Sp&ochim. Acta 19, 592 (1963). (82) Pernarowski, M., Knevel, A . M., Christian, J. E., J . Pharmaceu. Sci. 51, 688 (1962). (83) Phillips, J. P., ANAL. CHEM. 34, 171 (1962). (84) Phillips, J. P., Nachod, F. C., eds., “Organic Electronic Spectral Data, 1958-59,” Vol. IV, Wiley, New York, 1963
(85) Pobiner, H., Wallace, T. J., Hofmann, J. E., Zbid., 35, 680 (1963). (86) Rau, c. N. R., “Ultra-Violet and Visible Spectroscopy: Chemical Applications,” Butterworths, London, 1961. (87) Rendina, J . F., Rev. Sci. Znstr. 34, 813 (1963). (88) Riegelman, S.,Fischer, E. Z., J. Pharmaceu. Sci. 51, 206 (1962). (89) Rinehart, R. W., Stafford. J. E.. Microchem. J . 6 , 567 (1962). (90) Rosenbaum, E. J., Appl. Spectroscopy 17, 56 (1963). (9:) Sadtler Research Lab;ratories, Sadtler Standard Spectra, Ultraviolet, 1517 Vine Street, Philadelphia 2, Pa. (92) Sawicki, E., Stanley, T. W., Pfaff, J., D’Amico, A., Talanta 10, 641 (1963). (93) Schroeder, D. J., J . Opt. SOC.Am. 52, 1380 (1962). (94) Schwarberg, J. E., Mosihier, R. W., ANAL.CHEM.34, 525 (1962). (95) Shapira, R., Anal. Biochem. 3, 308 ( 1962). (96) Shurcliff, W. A., “Polarized Light: Production and Use,” Harvard Univ. Press, Cambridge, Mass., 1962. (97) Siegel, L., Hannan, R. B., SOC. Plastics Eng. J . 19, 1103 (19133). (98) Silverstein, R. hI., Bassler, G. C., “Spectrometric Identification of Organic Compounds,” Wiley, New York, 1963. (99) Simmons, I., Appl. Spectroscopy 17, No. 5. 18.4 (1963). (100) Slavin, ‘W., >. Opt. SOC.A m . 52, 1390 (1962). (101) Slavin, W., ANAL.CHEM.35, 561 ( 1963). (102) Smith, R. C.. Ret,. Sci. Instr. 34. 296 (1963). (103) Spears, A. W., ANAL. CHEM.35, 320 (1963). (104) Spurny, Z., Talanla 9, 885 ( 1962). (105) Stahl, C. R., ANAL. CHEM. 34, 980 ( 1962). VOL. 36, NO. 5, APRIL 1964
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(106) Stein, R. A., Slawson, V., Zbid., 35, 1008 11963). (107) Stephenson, W. H., Anal. Chim. Acta 28, 597 (1963). (108) Svehla, G., Pall, A., Erdey, L., Talanta 10, 719 (1963). (109) Thomuson. H. W.. “Advances in Spectroscdpy,” Vol. 11, pp. 429-472, Interscience, New York, 1961. (110) Trudell, L., Boltz, D. F., ANAL. CHEM.35, 2122 (1963). (111) Tweet, A. G., Rev. Sci. Instr. 34, 1412 (1963). (112) Ulrich, W. F., “Developments in Applied Spectroscopy,” Ferraro, J. R., Ziomek, J. S eds., pp. 130-141, Plenum Press, kew York, 1963. ( 13) Ungnade, H. E., “Organic Electronic Spectral Data,” Vol. 11, 1953-5, Interscience, Kew York, 1960. ( 14) Vandenbelt, J. M., J . Opt. SOC. Am. 52, 284 (1962). ~
(115) Vandenbelt. J. M.. Avvl. .. Svectros. copy 17, 120 (1963). (116) Vandenbelt, J. M., ANAL.CHEM 35, No. 7, 69A (1963). (117) Van Es, W. L., Wisse, J. H., Anal. Biochem. 6, 115 (1963). (118) Wagener, G. N., Grand, C. G., Rev. Sa’.Instr. 34, 540 (1963). (119) Walker, P. ?VI. B., Leonard, J., Gibb, D., Chamberlain, P. J., J. Sci. Instr. 40, 166 (1963). (120) Weaver, W. J., Reschke, R. F., J . Pharmaceu. Sci. 52, 363 (1963). (121) Weber, C. W., Howard, 0. H., ANAL.CHEM.35, 1002 (1963). (122) Weber, W. J., Morris, J. C., Stumm, W., Zbid., 34, 1844 (1962). (123) Wexler, A. S., Ztrid., 35, 1936 (1963). (124) White, J. C., “Progress in Nuclear Energy,” Series IX, “Analytical Chemistry,” Vol. 2, Crouthamel, E. E., ed., I
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Chap. 6, pp. 257-312, Pergamon Press, n’ew York. 1961. (125) Williams, D. M., Photochem. and Photobiology 1, 273 (1962). (126) Winefordner, J. D., St. John, P. A., ANAL.CHEM.35, 2211 (1963). (127) Wolken, J. J., Strother, G. K., App2. Optics 2, 899 (1963). (128) Wood, W. A., Gilford, S. R.,>Anal. Biochem. 2, 589 (1961). 1129) Wood. W. A.. Gilford. S. R.. Ibzd., 2, 601 (1961): (130) Yakovlev, S. A,, Optics and Svectroscopy 14, No. 5, 378 (1963). (131) Yankeelov, J. A., Anal. Biochem. 6 , 287 (1963). (132) Zimmerman, N., ANAL.CHEM.34, 710 (1962). (133) Zscheile, F. P., Jr., Murray, H. C., Baker, G. A., Peddicord, R. G., Zbid., 34, 1776 (1962). ~
X-Ray Absorption and Emission William 1. Campbell and James D. Brown, Bureau o f Mines, College Park Metallurgy Research Center, Ihterior, College Park, Md.
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over a decade Liebhafsky, more recently in collaboration with Winslow and Pfeiffer, has prepared fundamental reviews on x-ray absorption and emission (676-278). These reviews have provided excellent milestones to gauge the rapid progress of x-ray analysis. The present review uses their format of a critical review of fundamental developments and tabular summaries of applications of x-ray spectrography and electron probe microanalysis. Progress in x-ray analysis over a similar period was summarized a t an ASTM Symposium on X-Ray Spectrography and Electron Probe Microanalysis held in June 1963 (426). The most significant advances have been to extend the range of application to include elements of atomic numbers 11 to 92, to lower the limits of detection from parts per thousand to parts per million, to increase the usage of automation including sample presentation and data readout, and to provide reliable commercially available electron probe microanalyzers. All of these advances are discussed in this review, which covers the period from December 1961 to Kovember 1963. I n this review, the authors have emphasized the fundamental advances achieved in x-ray spectrography and electron probe microanalysis. h s a result, approximately 15y0of the papers listed were published prior to 1961 but were not included in the earlier reviews. The tremendous volume of x-ray literature falls into two principal categories: fundamental papers on excitation, dispersion, and general analytical OR
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theory, and applications for specific elements in specific classes of samples. These papers on specific applications account for the majority of the current literature. Unfortunately, many of them are repetitious. One should no longer be surprised to find that general analytical procedures can be applied to a number of elements in various types of samples. In most instances, the description of the chemical and physical treatment of the sample is the author’s only worthwhile contribution to x-ray analysis. Recent textbooks, symposia, and conference proceedings are listed in Table I. These textbooks are recommended additions to the personal library of all x-ray analysts. The “Encyclopedia of X-Rays and Gamma-Rays” (101) is an indexed compilation of papers rather than a true encyclopedia. As expected from such multiple authorship, the quality of papers ranges from excellent to mediocre. The publication of conference proceedings is strongly encouraged. However, in some instances only a small fraction of the papers &re related to x-ray analysis. Also, there is an increasing tendency to include in these proceedings papers that have already been published in technical journals or as government reports. This duplication of publications is of questionable value. The training of personnel is mainly the function of individual laboratories. Most univer3ities devote little time to a discussion of even rudimentary aspects of x-ray spectrography. The best introduction to this subject is provided by the instrument manufacturers. As part
U. S .
Department o f the
of their sales promotion, these manufacturers conduct excellent training coursein x-ray theory and techniques. Works shops on x-ray analysis held as part of general conferences on spectroscopy also are valuable training aids. ABSORPTION
There have been no significant fundamental advances in absorption analysis during the past two years. X-ray instrumentation developments are discussed under emission. -4discussion of x-ray mass absorption coefficients is included in the section on electron probe microanalysis. Previous reviews (276art?), recent general papers (13.9, 1B.5, 198-201, 207, 473) , and the following analytical applications adequately summarize x-ray absorption: sulfur in oil (163, 154, 185, 373), chlorine in organic compounds (192), cobalt in hydrocarbons (373) and in aqueous solutions (198), plutonium in metal castings (267), T B P in kerosine-base solvents (146), composition of solders (339), lead and barium in glass (339), and evaluation of column-chromatographic separation of iodine- and bromine-containing compounds (340). Instrument development includes single-crystal (653) and double-crystal spectrometers ( 2 @ ) , the latter having a multisample changer. Absorption methods for control analyses, using radioactive isotopes as the x-ray source, will continue to increase in popularity because of their low cost and high reliability. However, x-ray absorption is not as satisfactory as emission for use as a general analytical tool. Emission has the advantages of
