Environ. Sci. Technol. 1993, 27, 557-561
(36) Snyder, L. J. Chromatogr. 1974, 92, 223-230. (37) Carlberg, G. E.; Kringstad, A. In Analysis of Organic
(22) Haario, H.; Taavitaainen,V. M. Data-Analysis Toolbox for (23) (24) (25) (26) (27) (28) (29)
Use with Matlab, Users Guide, Control CAD, Espoo, Finland, 1991. Gergov, M.; Priha, M.; Talka, E.; Kilttila, 0.;Kangas, A.; Kukkonen, K. Tappi J. 1988, 71 (12), 175-184. Saunamaki, R.; Jokinen, K.; Jarvinen, R.; Savolainen, M. Water Sci. Technol. 1991,24 (3/4), 295-307. Bryant, C. W.; Amy, G. L.; Neill, R.; Ahmad, S. Water Sci. Technol. 1988, 20 (l),73-79. Cook, C. R. Proceedings;CPPA Environmental Conference, Vancouver, BC, Canada, 1988. Lindstrom,K.; Mohamed, M. Nord. Pulp Pap. Res. J. 1988, 3 (l),26-33. Aprahamian, E.; Stevens, S. Proceedings;TAPPI Pulping Conference, Tappi Press: Atlanta, GA, 1990; pp 209-215. Stuthridge, T. R.; Campin, D. N.; Langdon, A. G.; Mackie, K. L.; McFarlane, P. N.; Wilkins, A. L. Water Sci. Technol.
Micropollutants in Water;Bjorseth, A., Angeletti, G., Eds.; EUR 8518; Reidel: Holland, 1984; pp 276-279. (38) Martinsen, K.; Kringstad, A.; Carlberg, G. E. Water Sci. Technol. 1988,20,13-24. (39) Stachel, B.; Lahl, U.; Zeschmar, B. Sci. Total Environ. 1984, 40, 103-113. (40) Goring, D. A. I. In Lignins. Occurrence, Formation,
Structure and Reactions;Sarkanen, K. V., Ludwig, C. H., Eds.; Wiley Interscience: New York, 1971; Chapter 17, p 742. (41) Mori, S. In Steric Exclusion Liquid Chromatographyof
Polymers;Janca, J., Ed.; Chromatographic Science Series 25; Marcel Dekker, Inc.: New York, 1984; Chapter 4. (42) Bethge, P. 0.;Frisk, Y.; Hardell, H.-L. Report No 63 from the SSVL Project "Environment go", STFI-Meddelande A 985, Oct 1989; pp 25-26. (43) Pellinen, J.; Joyce, T. W. Pap. Timber 1991,73,527-531. (44) Tomar, P.; Allen, D. G. Water Pollut Res. J . Can. 1991,
1991, 24 (3/4), 309-317. (30) Bryant, C. W.; Amy, G. L.; Alleman, B. B. J.-Water Pollut. Control Fed. 1987,59, 890-896. (31) Payne, J. W.; Gilwarg, C. J. Biol. Chem. 1968, 243, 6291-6294. (32) Opgenorth, H.-J. In Umweltvertraglichkeit von Wasch-und
Reinigungsmitteln (EnvironmentalSafety of Laundry and Cleaning Agents); Oldenbourg, R., Ed.; Verlag GmbH: Munchen, 1990; pp 338-351. (33) Bryant, C. W.; Amy, G. L. Proceedings;TAPPI Environmental Conference, Tappi Press: Atlanta, GA, 1988; pp 435-438. (34) Fitzsimons, R.; Ek, M.; Eriksson, K.-E. Environ. Sci. Technol. 1990, 24, 1744-1148. (35) Amy, G. L.; Bryant, C. W.; Alleman, B. C.; Barkley, W. A. J.-Water Pollut. Control Fed. 1988, 60, 1445-1453.
26 ( l ) , 101-117. (45) Joshi, B. K.; Hillaby, B. J. Environmental fate and effects
of bleached pulp mill effluents;Sijdergren,A., Ed.; Swedish Environmental Protection Agency Report 4031; 1991; pp 101-109.
Received for review July I, 1992. Revised manuscript received October 27, 1992. Accepted October 28, 1992. This work was supported by the Maj and Tor Nessling Foundation and by Nordic Industry Fund Environmental Biotechnology Program A.2.1, with the industrial partners Alko Oy, Cultor Ltd., and Ekokem Oy.
Mass Spectrometric Evidence for the Formation of Bromochloramine and N-Bromo-N-chloromethylamine in Aqueous Solution Mlchael Gatda, Llndy E. DeJarme,Tarun K. Choudhury, R. Graham Cooks,* and Dale W. Margerum"
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 Membrane introduction mass spectrometry (MIMS) is used to confirm the existence of bromochloramine and N-bromo-N-chloromethylaminein aqueous solution, which have been proposed previously from UV-visible spectra. Bromochloramine is detected by mass spectrometry and UV-visible spectroscopy as a product of monochloramine reactions with bromide ion and with hypobromous acid. The reaction of HOBr with NH2Cl is at least 3 orders of magnitude faster than the reaction of Br- with NH2C1at pH 6.5. UV-visible studies also confirm NHBrCl as a product in the following reactions: NH2Cl + NH2Br, NH2Cl NHBr,, and NH2Br HOC1. N-Bromo-Nchloromethylamine is detected by mass spectrometry and UV-visible spectroscopy in the reaction of N-chloromethylamine with hypobromous acid.
+
+
Introduction Hypochlorous acid and chloramines are commonly used in water disinfection. Identification of reaction products in the chlorination process is essential in (a) determining water quality and (b) isolating potential health and environmental hazards. Bromide ion is commonly found in water systems, and the reaction of hypochlorous acid with bromide yields hypobromous acid as a product (1). Thus, the reactions of chloramines with bromide and hypobromous acid are of vital importance in the water treatment process. The chemistry, however, is complicated due 0013-936X/93/0927-0557$04.00/0
to the formation of a number of reactive hdoamine species. The reactions between NH2Cl and Br- have been examined in several studies (2-4). Trofe, Inman, and Johnson (2) first proposed a mixed haloamine as one of the products of this reaction. Bromochloramine was proposed on the basis of a UV-visible absorption maximum observed at a wavelength that lies between the absorption maxima for NHCl, (206 nm) and NHBr2 (232 nm). They reported a ,A, of 220 nm with t = 2100 M-' cm-' in aqueous solution of 218 nm in ether. They observed the aband a A,, sorption maximum associated with this product in ether extracts of the reaction mixtures shown in eqs 1-4. NH2C1+ Br-
---
+ HOBr NH,Br + HOC1 NH2Cl + NHBr, "$21
products
(1)
products
(2)
products
(3)
products
(4)
Other workers ( 3 , 4 ) ,who examined the NHzCl + Brreaction, concurred that NHBrCl is the probable product. However, the compound has not been isolated and its chemical composition has not been proven. Valentine (5) examined the oxidation of N,N-diethylp-phenylenediamine by a mixture of NH2Cl and NHBrCl and reported that the bromine atom in NHBrCl is very labile. This author proposed molar absorptivities in water
0 1993 American Chemlcal Soclety
Environ. Scl. Technol., Vol. 27,
No. 3, 1993 557
for NHBrCl of 712 M-l cm-l at 245 nm and 300 M-' cm-' at 320 nm. Haag and Jolley (6) presented UV-visible spectra in ether for species assumed to be NHBrCl and NBr2C1. These compounds were proposed to form by eqs 5 and 6 (6-9). These authors estimated the aqueous spectral NHzCl + HOBr NHBrCl + H,O (5) (6) NHBrCl + HOBr NBr,Cl + H 2 0 characteristics of NBrzCl as A,, ~ 2 4 nm 0 and e = 6000 M-' cm-' and suggested that both NHBrCl and NBr2Clare important haloamines formed in the chlorination of seawater. Haag (7, 8) proposed the formation of N-bromo& chloromethylamine,according to eq 7, based on 'H-NMR, (7) CH3NHC1+ HOBr CH3NBrC1+ HzO IR, and UV-visible spectral characteristics that are intermediate between those of CH3NBr2 and CH3NC12. Haag reported absorbance maxima in aqueous solution for CH,NBrCl at 223 nm (e = 2760 M-' cm-') and at 328 nm (e = 350 M-' cm-I). The proposed mixed haloamine, CH3NBrC1is relatively stable in aqueous solution (t,,, = 170 h at pH 8.2) (7,8). Unlike NHBrC1, CH3NBrC1has been characterized, but only in organic solvents (7,8,10). In the present work, unequivocal evidence for the formation of mixed haloamines in aqueous solution is sought by use of membrane introduction mass spectrometry (MIMS) (11). MIMS is an analytical method that allows direct monitoring of aqueous solutions at atmospheric pressure via an interface to a mass spectrometer that operates under conventional high-vacuum conditions. The technique is based on the selective pervaporation of analytes though a semipermeablemembrane into the vacuum of a mass spectrometer. The membrane used in the experiment acts as a selective barrier to polar and ionic species and allows nonpolar volatile compounds to pass into the mass spectrometer. This technique has been successfully used to monitor dissolved gases (12,13) and volatile organic compounds in aqueous solutions (11). It has also been applied to monitor environmentally significant samples (14-16) and for on-line monitoring of bioreactors (17-19). By locating the membrane in a direct insertion membrane probe, fast response time (typically 5-30 s) and low detection limits (often low ppb levels) are achieved (13,20,21).MIMS has already proven useful in the detection of organic and inorganic chloramines (22-25). In the present work, three systems are examined by the MIMS technique: NH,Cl+ Br-, NHzCl HOBr, and CH3NHC1+ HOBr.
--
+
Experimental Section Preparation of Haloamines. Monochloramine solutions were prepared by combining solutions of hypochlorite with 10% excess ammonia at pH 11. Monobromamine solutions were prepared by combining solutions of hypobromite and ammonia a t pH 11, with ammonia in 50% excess. The monobromamine solutions were used immediately after preparation, because they decayed within a few minutes. Dibromamine solutions were prepared by allowing NHzBr solutions to stand at pH 7. The NH,Br decayed rapidly to NHBr, at this pH, and the NHBr, formed was stable for several minutes. Solutions of N chloromethylaminewere prepared by combining solutions of methylamine and hypochlorite with methylamine in 4-fold excess. UV-Visible Spectroscopy. A Perkin-Elmer Lambda 9 UV-visible-ne& IR spectrophotometer was used to obtain UV-visible spectra of ether extracts of the reactions 558 Envlron. Scl. Technol., Vol. 27, No. 3, 1993
in eqs 1-4 and 7, and the reaction of "$1 with NH2Br. Initial concentrations of the reactions were 1 mM after mixing, unless otherwise indicated. A 1.0-cm cell was used in all experiments. Details for each reaction follow. NH,C1+ Rr-. This reaction was run with 50-fold excess Br- in 25 mM phosphate buffer (pH 7). The reaction was allowed to proceed for 100 s (the approximate half-life for the loss of NH,Cl) before extraction into ether. NH,Cl + HOBr. This reaction was run with a 1:l mole ratio of reactants at pH 7, and the reaction mixture was extracted within 5 s of mixing. N H a r + HOC1. This reaction was run at pH 11,where NHzBr is stable for several minutes. Immediately after preparation of NH2Br,an equimolar amount of HOC1 was added, and the reaction mixture was extracted with ether within 5 s. NH,CI + NHBr2. This reaction was run at pH 7 with a 1:l mole ratio and extracted in less than 5 s. NH,CZ + NH&. This reaction was run at pH 11with a 1:l mole ratio. Immediately after preparation of NH,Br, "$21 was added and the reaction mixture was extracted within 5 s. CHJVHCI HORr. This reaction was run with a 1:l mole ratio at pH 7, and the reaction mixture was extracted in 40 s. Membrane Introduction Mass Spectrometry. Mass spectra were obtained by using a Finnigan TSQ 4500 triple-quadrupole instrument equipped with an INCOS data system. One quadrupole was used for mass analysis of the ions produced in the ion source, while the other two quadrupoles were operated in the rf-only mode. Ions were produced under 70-eV electron impact ionization conditions. The source temperature was maintained at 190 "C while the manifold temperature was set at 120 "C. A flat sheet of dimethylvinyl silicone polymer membrane (ASTM, VMQ Dow Corning) with a thickness of 0.005 in. was mounted in a specially constructed direct insertion probe (20). The probe was inserted into the ion source of the mass spectrometer. Contact of the probe with the source block was made so that the membrane formed one of the walls of the heated ion source of the mass spectrometer. The membrane probe was internally heated to 70 "C by a built-in heater operated by a programmable temperature controller. A peristaltic pump (Ismatic, Model 7618-30) was used to transport the solution through the probe and across the membrane. The flow rate was 1mL/min. The aqueous samples were initially at room temperature (20 "C), and they were in the probe for only a few seconds. The reactants were mixed at the time the sample was introduced into the membrane probe, and the initial signal detection was typically 16 s after introduction. The reactions shown in eqs 1,2, and 7 were carried out and the reaction mixtures were monitored by MIMS. Details of each reaction follow. NH,CZ + Rr-. The "$1 concentration was initially 4 mM after mixing with a 12-fold excess of Br-. The solution was buffered with phosphate at pH 6.5. NH,Cl + HOBr. These reagents were combined in a 1:l mole ratio each at 2 mM after mixing. The solution was buffered with phosphate at pH 6.5. The mass spectrometer was set to scan from 35 to 300 amu/charge. CHJVHCl+ HOBr. These solutions were combined in a 1:l mole ratio, so that the concentration of each was 2 mM after mixing. The solution was buffered at pH 6.5 with phosphate.
+
Results and Discussion UV-Visible Spectroscopy Results. Details for each reaction follow.
1 .0
100
I A=
NH,"CI
8
mlz 51
n
.-
L
solution introduction
0 ' 200
280
320
360
400
wavelength, nm
+
Flgure 1. UV-visible spectra (1-cm cell) in ether of (a) NH2CI Br-, 1 5 0 mole ratio, pH 7, extraction after 100 s; (b) NH,CI 4- HOBr, 1:l HOBr, 1:l mole ratio, pH 7, extraction after 5 8; and (c) CH,NHCI mole ratio, pH 7, extraction after 40 s.
+
+
NH,CZ Br-. Product peaks assigned to NHBrCl at 220 and 330 nm are evident in the UV-visible absorption spectrum of the ether extract (Figure la). A shoulder due to unreacted NHzCl at 255 nm is also present. NH2C1 + HOBr. The ether extraction spectrum (Figure lb) shows peaks at 220 and 330 nm due to NHBrC1. I t also has a peak of 248 nm which was proposed by Haag and Jolley (6) to be due to NBrzC1. Spectra of aqueous solutions show a peak at 242 nm with a molar absorptivity substantially larger than NHzCl (Arnm = 243 nm, e = 461 M-' cm-') (26). This corresponds to the predicted spectrum of NBr2C1. N H a r HOC1. Peaks characteristic of NHBrCl were observed at 220 and 330 nm in the spectrum of the ether extract. NH2C1 NHBr,. The ether extraction spectrum showed peaks at 220 and 248 nm, indicative of NHBrCl and NBrzC1. NH2C1 + N H a r . The ether extraction spectrum showed peaks at 220 and 330 nm, characteristic of NHBrC1. CHJVHCI + HOBr. The ether extraction spectrum showed bands proposed by Haag (7,8) for CH3NBrCl as shoulders at 223 and 328 nm (Figure IC). Another shoulder at 240 nm was attributed to CH,NBrz (7, 8). Membrane Introduction Mass Spectrometry Results. Details of the ion abundances as a function of time and mass spectra for the reactions monitored by MIMS are described below. NH&Z Br-. Ions with m/z values of 51 (NH235Cl'+), 53 (NH237CY+),129 (NH79BrW1.+),131 (NH79B$7Cl'+ and NHs1Br35C1'+),and 133 (NHs1Br37C1*+) were monitored using multiple-ion detection (MID). These are the expected ions for the major isotopic forms of monochloramine and bromochloramine. Prior to the introduction of the reaction mixture, background signals were monitored during the first 84 s, as shown in Figure 2. The reaction mixture was introduced at 84 s and continued to flow over the membrane for more than 500 s. The signal due to the components in the mixture appeared at 100 s (or 16 s after introduction of the reaction mixture). Figure 2 shows the abundances of two of the five ions monitored as the reaction proceeded. Their behavior is identical to that of the other isotopic forms of the reactant and product. The ion due to the reactant, NH235Cl'+( m / z 51), rises steeply and peaks at about 110 s; this corresponds to a response time of 10 s. This is similar to the response time of the silicone membrane (27)for other volatile compounds. The monochloramine signal shows a first-order decay. The lower part of Figure 2 shows the formation and decay of
+
+
+
m/z 129
at 100seconds
I
240
0
20
40
60
80
90
0
04
169
253
337
421
100
scan
506 time,s
Flgure 2. Ion abundances of NH,Ci'+ (m/z 51) and NHBrCi'+ (mlr 129) during oMlne monitoringof the reactlon of NH,CI 4- Br, 1:12 mole ratio, pH 6.5, using multiple-ion detection.
and Br-
Table I. MID Mass Spectrum of the "$31 Reaction Mixture" mlz
assignmt of ions
51 NH,35C1'+ 53 NH:"C1'+ 129 NH79Br35C1'+ 131 NH79Br37CI.+; NH81Br36C1'+ 133 NH81Br37C1'+
obsd % re1 abund
calcd % re1 abundb
100
32 23 29
100 32 24 29
6
7
"Taken between 126 and 168 s according to the time scale shown in Figure 2. *Calculated from average natural abundances.
m / z 129, the molecular ion of bromochloramine, NH79Br35Cl'+.The signal for this ion appears at 100 s and reaches a maximum a t about 210 s. The 110-s interval between the peaks for the monochloramine ion and the bromochloramine ion corresponds to the conversion of monochloramine to bromochloramine and the subsequent decay of bromochloramine in the reaction mixture. The mass spectrum of the reaction mixture taken between 126 and 168 s is given in Table I together with the expected relative abundances for monochloramine and bromochloramine molecular ions. The quantitative agreement between the expected and observed relative abundances of the isotopic mixture confirms that the product formed is indeed bromochloramine. In order to investigate products other than the bromochloramine that may have been formed in the reaction vessel, a separate experiment was performed in which the mass spectrometer was set to scan over the full range from 35 to 300 amu/charge. No ions were observed above m/z 140, and Figure 3 shows the mass spectrum in the mass range between 40 and 140 amu/charge. The spectrum shows the presence of bromochloramine ions with the expected isotopic pattern. The ions clustered around m/z 95 are products of fragmentation of the bromochloramine brought about by the loss of C1 and HC1 respectively. Two sets of ions of similar abundances are present: NH79Br+ (m/z 94) and NHBIBr+( m / z 96); N7gBr*+(m/z 93) and NBIBr*+( m / z 95). Another cluster of ions is observed around m/z 80. These ions correspond to 79Br+(m/z 79), H79Br'c (m/z 80), "Br+ (m/z 81) and HslBr*+( m / z 82). NH2Cl + HOBr. The mass spectrum recorded for this reaction mixture (Figure 4) has the same features seen in Figure 3 with regard to the ions observed and their relative intensities. This result confirms that bromochloramine is also formed in the reaction between monochloramine and hypobromous acid. The monochloramine reaction Environ. Sci. Technol., Vol. 27, No. 3, 1993 558
I1
1001
e, 0
c 0 D 3
n
a Q
50
.-oQ
. I -
I
NH CI 2
+
Table 11. Mass Spectrum for N-Chloromethylamine and HOBr Reaction Mixture
1
% re1
mlz 62 63 64 65
1 1 I
Dc
R
NBr
+.
66 67 79
+.
NHBrCl
80 81 82
108 110 143 145 147 187 189 191
m/z Figuro 3. Full mass spectrum for an experiment wlth NH&I 4- Brtaken In the interval 126 and 186 s after mixing under the same conditions used to record the Ion abundances In Figure 2.
+.
NHBrCl
loo,
abund
assignmt of ions CHN35C1+ CH2N3jC1+ CH3N3T1+ CH3NH35Cl'+; CH2N3T1+ CH3N3W+ CH3NH37C1'+ 79Br+ H79Br'+ alBr+ HalBr'+ CH3NTgBr+ CH3NB1Br+ CH3N79Br35C1'+ CH3Ns1Br35C1'+; CH3N79Br37C1'+ CH3NB1Br37C1'+ CH3N79Brz'+ CH3N79Bra1Br'+ CH3Ns1Br2'+
'"1 I
1
CH3NBrCI
13
100 85 78 33
20 63 16 67 20 25 18
75 97 26 5 9 4
+.
(u
e,
0
0
v
3
z
c
0
0
c
U
3
n
a e,
.-> -0a, Y
Dc
R
R
m/z
m/z Flguro 4. Mass spectrum for the reaction mlxture of NH,CI and HOB, 1:l mole ratlo, pH 6.5.
with hypobromous acid is at least 3 orders of magnitude faster than the corresponding reaction of monochloramine with bromide ion, as indicated by the absence of monochloramine in the mass spectrum. This is in agreement with stopped-flow spectrophotometric results (28). The bromochloramine is slower to decay in the absence of excess bromide. No signal for NBr2C1is evident, which may be due to the limited permeability of the membrane to this compound. Further studies of the properties of these and other membranes are in progress. CHflHCl+ HOBr. The mass spectrum for this reaction mixture is shown in Figure 5, while Table I1 summarizes the assignments of the major isotopic forms to the peaks in the mass spectrum. The tabulated spectrum shows isotopic patterns that confirm the presence of N-bromoN-chloromethylamine and N,N-dibromomethylamine. Fragmentation products which may arise from the halomethylamines are also observed. Unreacted N-chloromethylamine is present in high abundance, which indicates that is is less reactive with hypobromous acid than NH2C1.
Conclusion This work gives direct molecular evidence to support the proposals made by Trofe et al. (2)and Haag et al. (6-9) that bromochloramines are formed in the reactions of monochloramineswith bromide ion and with hypobromous 180 Envlron. Scl. Technol., Vol. 27, No. 3, 1993
Figure 5. Mass spectrum for the reaction mixture of CH,NHCi and HOBr, 1:l mole ratio, pH 6.5.
acid in aqueous solution. We have demonstrated that these reactions can be monitored in real time by using MIMS. This mass spectrometric method provides much more secure structural information than does UV-visible absorption. Nevertheless, limitations exist in membrane interfaces and some compounds may not be detected; in addition, the delay between mixing and signal observation may preclude the observation of short-lived species.
Literature Cited (1) Kumar, K.; Margerum, D. W. Inorg. Chem. 1987, 26, 2706-27 11. (2) Trofe, T. W.; Inman, G. W.; Johnson, J. D. Environ. Sci. Technol. 1980, 14, 544-549. (3) Valentine, R. L.; Selleck, R. E. In Water Chlorination: Environmental Impact and Health Effects;Jolley, R. L., Brungs, W. A., Cotruvo, J. A., Cumming, R. B., Mattice, J. S., Jacobs, V. A., Eds.; Ann Arbor Science: Ann Arbor, MI, 1983; Vol. 4, pp 125-139. (4) Bousher, A.; Brimblecombe, P.; Midgley, D. Water Res. 1989,23, 1049-1058. (5) Valentine, R. L. Environ. Sci. Technol. 1986,20, 166-170. (6) Haag, W. R.; Jolley, R. L. In Water Chlorination: Environmental Imwact and Health Effects: Jollev, R. L., Brungs, W. A.: Cotruvo, J. A,, Cumming, R. B.,Mattice; J. S., Jacobs, V. A,, Eds.; Ann Arbor Science: Ann Arbor, MI, 1983; voi. 4, pp 77-43. (7) Haag, W. R. In Water Chlorination: Environmental Zmpact and Health Effects: Ann Arbor Science: Jolley, R.
L., Brungs, W. A,, Cumming, R. B., Jacobs, V. A., Eds.; Ann Arbor, MI, 1980;Vol. 3, pp 191-201. (8) Haag, W.R. J . Inorg. Nucl. Chem. 1980,42,1123-1127. (9) Haag, W. R.; Lietzke, M. H. In Water Chlorination: Environmental Impact and Health Effects: Jolley, R. L., Brungs, W. A,, Cumming, R. B., Jacobs, V. A,, Eds.; Ann Arbor Science: Ann Arbor, MI, 1980;Vol. 3, pp 415-426. (10) Kearney, T. J.; Sansone, F. J. In Water Chlorination: Environmental Impact and Health Effects: Jolley, R. L., Bull, R. J., Davis, W. P., Katz, S., Roberts, M. H., Jr., Jacobs, V. A., Eds.; Lewis Publishers Inc.: Chelsea, MI, 1985;Vol. 5,pp 965-974. (11) Kotiaho, T.; Lauritaen, F. R.; Choudhury, T. K.; Cooks, R. G.; Tsao, G. T. Anal. Chem. l991,63,875A. (12) Degn, H.; Cox, R. P.; Lloyd, D. Methods Biochem. Anal. 1983,31,165-194. (13) Lloyd, D.; Bohatka, S.; Szilagji, J. Biosensors 1986, 1, 179-212. (14) Choudhury, T. K.; Kotiaho, T.; Cooks, R. G. Talanta 1992, 39. 573-580. (15) Hhland, B. J.; Nicholson, P. J. D.; Gillings, E. Water Res. 1987.21.107-113. (16) Lister, A. K.; Wood, K. V.; Cooks, R. G.; Noon, K. R. Biomed. Environ. Mass Spectrom. 1989,18, 1063-1069. (17) Heinzle, E.; Reuss, M. In Mass Spectrometry in Biotechnological Process Analysis and Control: Plenum: New York, 1987. (18) Jorgensen, L.; Degn, H. Biotechnol. Lett. 1987,9,71-76.
(19) Hayward, M. J.; Kotiaho, T.; Lister, A. K.; Cooks, R. G.; Austin, G. D.; Narayan, R.; Tsao, G. T. Anal. Chem. 1990, 62,1798-1804. (20) Bier, M. E.; Kotiaho, T.; Cooks, R. G. Anal. Chim. Acta 1990,231,175-190. (21) Bier, M. E.; Cooks, R. G.; Broadbelt, J. S.; Tou, J. C.; Westover, L. G., U.S.Patent 4,791,292,1989. (22) Kotiaho, T.; Lister, A. K.; Hayward, M. J.; Cooks, R. G. Talanta 1991,38,195-200. (23) Kotiaho, T.; Wood, J. M.; Wick, P. L., Jr.; Dejarme, L. E.; Ranaainghe, A.; Cooks, R.G.; Ringhand, H. P. Environ. Sci. Technol. 1992,26,302-306. (24) Savickas, P.J.; LaPack, M. A.; Tou, J. C. Anal. Chem. 1989, 61,2332. (25) Kotiaho, T.; Hayward, M. J.; Cooks, R. G. Anal. Chem. 1991,63,1794. (26) Kumar, K.;Day, R. A.; Margerum, D. W. Inorg. Chem. 1986, 25,4344-4350. (27) Lauritaen, F.R.; Choudhury, T. K.; Dejarme, L. E.; Cooks, R. G. Anal. Chim. Acta 1992,266,1-12. (28) Gazda, M.; Margerum, D. W. Purdue University, to be submitted for publication. Received for review July 30,1992.Revised manuscript received November 8,1992.Accepted November 16,1992. This work was supported by National Science Foundation Grants CHE-9024291 (D.W.M.)and CHE-8721768(R.G.C.).
Envlron. Scl. Technol., Vol. 27, No. 3, 1993 561
