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spectral interferences originating from serum can be avoided, thus enhancing the accuracy and precision. In addition, after modification this immunoreactor can easily be applied in a continuous flow system. Registry No. CK, 9001-15-4.
LITERATURE CITED (1) Sax, S. M.; Moore, J. J.; Grlegel, J. L.; Welsh, M. Ciin. Chem. (Wlnston-Salem, N . C . ) 1976, 22, 87-91. (2) Roberts, R.; Henry, P.; Wttenveen, S.; Sobel, B. E. Am. J . Cardiol. 1974, 33, 650-655. (3) Yasmineh, W. G.; Hanson, N. 0. Ciin. Chem. (Winston-Salem, N.C.) 1975, 27, 381-386. (4) Galen, R. S.;Bambino, S. R., Clin. Chem. (Winston-Salem, N.C.) 1975, 27, 1848-1850. (5) Schlabach, T. D.; Futon, J. A.; Mochrldge, P. B.; Toren, E. C., Jr. Anal. Chem. 1980, 52, 729-733. (6) Chang, S. H.; Goddlng, K. M.; Regnier, F. E. J . Chromatogr. 1976, 725, 103-110. (7) Kuderka, P. J.; Busby, M. G.; Carey, R. N.; Toren, E. C., Jr. Clin. Chem. (Winston-Salem, N.C.)1975, 21, 450-452. (8) Wurzburg, V.; Hernrich, N.; Orth, H.-D.; Lang, H.; Prelllwltz, W.; Neumeler, D.; Knedel, M.; Rick, J. J . Clln. Chem. Clln. Biochem. 1977, 75, 131-137. (9) Wicks, R.; Vsategui-Gomez, M.; Miller, M.; Warshaw, M. Clin. Chem. (Wlnston-Salem, N.C.)1982, 28, 54-58. (10) Wu, A. H. B.; Bower, G. N., Jr. Clln. Chem. (Winston-Salem, N.C.) 1982, 28, 2017-2021.
(11) Whelam, P. V.; Malkus, H. Clln. Chem. (Winston-Salem,N.C.)1983, 29, 1411-1414. (12) Mercer, D. Clin. Chem. (Winston-Salem, N.C.) 1976, 2 2 , 552-554. (13) Itano, M. Am. J . Chem. Pathol. 1976, 65, 351-355. (14) Galen, R. S.Clin. Chem. (Winston-Salem, N . C . ) 1976, 2 2 , 120. (15) Wicks, R.; Usategue-Gomez, M.; Warshaw, M. Clin. Chem. (WinstonSalem, N.C.)1982, 2 8 , 54-58. (16) Weetall, H. H. In "The Chemistry of Biosurfaces"; Hair, M. L., Ed.; Marcel Dekker: New York, 1972; VoI. 2. (17) Line, W. F., Becker, M. J. In "lmmoblllzed Enzymes, Antigens, Antibodies and Peptldes"; Weetall, H. H., Ed.; Marcel Dekker: New York, 1975; Vol. 1. (18) Sllman, I . H.; Katchalskl, E. Annu. Rev. Biochem. 1966, 32, 873-877. (19) Wellky, N.; Weetall, H. H. Immunochemistry 1965, 2 , 293-297. (20) Wlllson, V. J. C.; Jones, H. M.; Thompson, R. J. Clin. Chim. Acta 1981, 773, 153-156. (21) Yuan, C. L.; Kuan, S. S.; Guilbault, G. G. Anal. Chim. Acta 1981, 724, 169-176. (22) Deutsche Gesellschaft fur Klimische Chemle Z. Klin. Chem. Klin. Biochem. 1972, 70, 182-187. (23) Yuan, C. L.; Kuan, S. S.;Guilbault, G. G. Anal. Chem. 1981, 53, 190-193. (24) Regnier, F . E.; Noel, R. J . Chromafogr. Sci. 1976, 14, 316-320. (25) Royer, G. P.; Llberatore, F. A,; Grace, G. M. Biochem. Blophys. Res. Commun. 1975, 64, 478-485.
RECEIVED for review November 16,1984. Resubmitted June 3, 1985. Accepted June 3, 1985.
Use of a Permeation Sampler in the Collection of 23 Volatile Organic Priority Pollutants Roger D. Blanchard and James K. Hardy*
Department of Chemistry, University of Akron, Akron, Ohio 44325
A method Is described for the tlme-weighted-average concentratlon determlnatlon of 23 volatlle organic priorlty pollutants uslng a permeation sampler. Collectlon Involves volatlie component permeatlon through a slllcone polycarbonate membrane and absorption onto charcoal contalned wlthln the sampllng devlce. Analysis conslsts of desorption of the volatile components wlth carbon dlsulflde and then separatlon and quantlflcatlon by caplllary column gas chromatography. A llnear reiatlonshlp exlsts between the amount of a volatile organic component collected and the product of the time of exposure of the sampllng devlce to the sampllng environment and the concentratlon of the component In the sampling environment, for the ranges investigated. Temperature is the only other external factor which has been shown to affect the rate of permeatlon, though the change In the permeatlon constant has been shown to be approximately h e a r with a slope of about 0.4. Preclslon and accuracy compare favorably wlth the purge and trap method. The sampllng procedure has the advantage of glvlng time-welghted-average concentratlon values without requirlng a power supply, the sampling devlce Is Inexpensive, the devlce can be reused over an extended period of time, and it is slmple to use.
The United States Environmental Protection Agency (EPA) has developed a list of 129 species called the Priority Pollutant List ( 1 ) . Contained within the list are 31 compounds classified as volatile organics. The present federally approved procedure for the determination of volatile organics is the purge and trap
technique (2,3). Grab sampling, pumping systems, or evacuated flasks are used in the collection of samples in this technique. The major limitation of grab sampling is that the sample obtained reflects conditions for only a short time period. Pumping and evacuation systems collect timeweighted-average samples but are expensive, may require power for pumping and/or refrigeration, have limited capacity, and may be bulky, all of which make multilocation testing difficult. A method which has the advantage of collecting time-weighted-averageconcentration values while stabilizing the sample, is simple and inexpensive, and requires no power would be desirable. Permeation through a synthetic membrane affixed to a collection device containing an appropriate collection medium can provide these advantages. Previous work in this laboratory (4) has demonstrated the use of permeation through a silicone polycarbonate membrane onto activated charcoal to collect the following six volatile organic priority pollutants: benzene, toluene, ethylbenzene, dichloromethane, chloroform, and carbon tetrachloride. Subsequent analysis comprises sample desorption with carbon disulfide and separation and quantification by gas chromatography. This work provided evidence of a linear relationship when plotting the amount of a compound collected by a collection device vs. the product of the concentration of the compound in an aqueous environment and the time that the collection device is exposed to the aqueous environment. This relation can be stated as
K = m/Ct
(1)
where m is the mass of component collected (micrograms), C is the concentration of the component in the aqueous en-
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Table I. Response Time Data peak no.
compound
response time, min
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
acrylonitrile 1,l-dichloroethylene dichloromethane trans-1,2-dichloroethylene 1,l-dichloroethane chloroform 1,2-dichloroethane l,l,l-trichloroethane benzene carbon tetrachloride 1,2-dichloropropane bromodichloromethane trichloroethylene 2-chloroethyl vinyl ether cis-1,3-dichloropropene trans-1,3-dichloropropene 1,1,2-trichloroethane toluene tetrachloroethylene chlorobenzene ethylbenzene bromoform 1,1,2.2-tetrachloroethane
1.8 2.6 2.2 1.2 2.0 2.5 4.6 2.8 2.8 2.7 6.4 5.0 6.0 10.5 7.6 7.6 7.2 3.4 8.3 9.0 4.0 10.6 14.0
vironment in parts per million, t is the time of the exposure period in hours, and K is the calibration constant for each specie with units of yg/(ppmh). This relationship had previously been demonstrated for air pollution monitors using t h e permeation technique by West e t al. (5-8). Permeation rate constants were obtained on each of the six priority pollutants both individually and simultaneously collecting the six compounds from one aqueous solution, with comparable permeation constant values. The present permeation device was evaluated for a number of environmental factors to determine what effect, if any, each would have. These included variations in temperature,ionic strength, pH, oxidant levels, humic acid levels, volatile acid levels, surfactant levels, and enhanced levels of dichloromethane in the simultaneous collection of the five other compounds. Temperature is the only factor that displays an effect on the permeation rate. The permeation rate increases in an approximately linear manner with increasing temperature. T o determine the concentration of a component with a permeation device where the average temperature of the sampling medium is known, requires the following equation:
c = m/(&
+ sT)t
where KOis the permeation rate constant at 0 "C, s is the slope of the temperature effect (dK/dT), T is the average temperature over the sampling period ("C), and C, m, and t are given in eq 1. This paper contains permeation rate constant and temperature effects results for 23 volatile organic priority pollutants. Table I contains a listing of the 23 volatile organic priority pollutants studied.
EXPERIMENTAL SECTION Apparatus. Initial evaluation to demonstrate linearity of response vs. concentration was accomplished with the permeation cell previously described (4). Also determined with this device was the response time, which is defined as the time necessary to achieve 90% of full response, and a demonstration of changes of the permeation rate with respect to variations in temperature. For the determination of response time and response vs. concentration, the solution reservoir was filled with varied concentrations of a solution containing one priority pollutant. The solution was allowed to flow through the permeation cell, which contains a silicone polycarbonate membrane (0.025 mm thick, General Electric). The organic compound permeates through the
9C Figure 1. Chromatogram of 23 volatile organics: column temperature, 30 OC for 8 min and then to 150 "C and 8 " C/min; injection temperature, 200 "C; detection temperature, 250 "C; linear velocity, 15 cm/s at 115 OC; He; split ratio 200:l; sample 1.0 yL; FID detection.
Table 11. Calibration Results and Ranges Investigated
compound acrylonitrile 1,l-dichloroethylene dichloromethane trans-1,2-dichloroethylene 1,l-dichloroethane chloroform 1,2-dichloroethane l,l,l-trichloroethane benzene carbon tetrachloride 1,2-dichloropropane bromodichloromethane trichloroethylene 2-chloroethyl vinyl ether 1,3-dichloropropene 1,1,2-trichloroethane toluene tetrachloroethylene chlorobenzene ethylbenzene bromoform 1,1,2,2-tetrachlorethane
K, pLp/(ppm. h)
1.02 12.4 13.2 15.6 14.2 12.2
10.7 14.8 15.7 15.3 12.7 13.1 17.6 7.3 15.3 9.2 13.5 12.4
10.7 12.2
11.0 7.6
ppm-h range
concn range, PPm
13.2-58.2 2.68-32.2 2.95-43.2 1.29-34.7 1.90-38.5 1.82-48.2 4.97-49.6 1.91-28.0 2.75-35.6 0.76-35.7 3.75-41.0 5.02-45.6 2.06-37.8 3.94-47.4 3.38-27.9 4.43-43.8 2.14-30.9 2.37-32.4 3.23-48.5 1.72-28.7 4.81-58.5 5.83-30.9
2.42-19.4 1.340-10.4 0.044-24.8 0.820-7.92 0.028-15.7 0.034-21.4 0.074-16.8 0.970-10.3 0.041-11.0 0.011-12.3 0.056-15.6 0.616-15.2 0.031-15.1 1.300-15.6 1.390-9.03 0.066-17.5 0.032-1 1.1 1.190-10.8 0.058-19.4 0.026-10.4 0.072-19.5 0.087-13.9
membrane and is then carried to a flame ionization detector of a gas chromatography by a nitrogen flow of 10 mL/min. The chromatograph used in this work was a Hewlett-Packard Model 5730A. The response was measured on a Linear Model 1200 strip chart recorder. Response VI. temperature information was collected in a similar manner, with the exception that the permeation cell was placed in a thermostated bath with the temperature varied continuously between 0 OC and 30 "C. Permeation constant and permeation constant vs. temperature data were obtained with the permeation device and exposure chamber previously described (4). An exposure involved placing 1 g of 200-mesh activated charcoal (Fisher Scientific) in a permeation device and placing the permeation device in an exposure chamber for measured periods of time. The exposure chamber contained component concentrations ranging from low partper-billion to low part-per-million levels. After exposure, the charcoal was transferred to 9-mL glass vials and sealed for storage. Analysis involved desorbing the charcoal with 5 mL of carbon disulfide for a minimum period of 30 min and injecting 1p L into a gas chromatograph, Hewlett-Packard Model 5730A. The columns used were a 1% SP-1000,60/80 mesh Carbopack B and an SPB-1 fused silica 60 m by 0.32 mm i.d. with a film thickness of 1.00 pm. The 1% SP-lo00 Carbopack B column was used prior to acquisition of the SPB-1fused silica capillary column. Complete separation of all compounds under investigation was not possible with the 1% SP-1000 on Carbopack B, but separation was achieved for all compounds under investigation with the SPB-1, as can be seen in Figure 1. The permeation device can be used over an extended period of time once the device has been calibrated, as long as the integrity of the membrane is maintained. No memory effect has been
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Anal. Chem. 1985, 57, 2351-2357
Table 111. Micrograms vs. Parts per Million Hours for Bromodichloromethane PPm.h 5.0 5.1 7.6 7.8 10.2 10.4 10.4 11.1
A%
63 80 119 109
152 130 168 163
RESULTS AND DISCUSSION
PPm*h
PLP
11.4 15.2 15.3 20.1 20.7 30.4 45.6
160 192 248 298 304 410 598
Table IV. Effect of Temperature on Permeation Constant compound acrylonitrile 1,l-dichloroethylene dichloromethane trans-1,2-dichloroethylene 1,l-dichloroethane chloroform 1,2-dichloroethane l,l,l-trichloroethane benzene carbon tetrachloride 1,2-dichloropropane bromodichloromethane trichloroethylene 2-chloroethyl vinyl ether 1,3-dichloropropene 1,1,2-trichloroethane toluene tetrachloroethylene chlorobenzene ethylbenzene bromoform 1,1,2,2-tetrachloroethane
sa,
K/OC
0.032 0.429 0.321 0.370 0.476 0.366 0.297 0.531 0.367 0.356 0.331 0.329 0.520 0.338 0.529 0.303 0.326 0.426 0.304 0.319 0.422 0.301
adsorb the permeated components was initially treated by thermal desorption at 350 “C with a nitrogen purge.
% change/OC
3.13 3.64 3.04 2.23 3.61 3.26 3.20 3.80 3.11 2.24
3.35 3.44 3.53 4.61 3.45 3.30 3.65 3.43 3.70 3.95 3.84 3.96
Slope of temperature effect as defined in eq 2. observed from repeated use, and the procedure can be mastered with a minimum of instruction. Reagents. All organic compounds used were reagent grade. Distilled water which had been passed through a charcoal filter (Barnstead) to remove oranic components was used in making stock solutions containing the volatile organic components. The stock solution was analyzed by gas chromatography and diluted to make exposure solutions. Carbon disulfide (Fisher Scientific) was used for desorption. Activated charcoal (200 mesh) used to
Linearity was demonstrated for response vs. concentration for all compounds tested over a concentration range from approximately 1 to 50 parts per million. The concentration range was limited at the lower level by the sensitivity of the detector-electrometer system and strip chart recorder. An upper limit of 50 ppm was set because concentrations above this level should not be expected in sampling environments. Response time data for all compounds studied are given in Table I. All response times are below 15 min. Permeation constant data and ranges investigated are given in Table 11. Permeation constants range from 1.02 Wg/ (ppmsh) for acrylonitrile to 17.6 hg/ (ppmBh) for trichloroethylene. Concentration ranges from the low part-per-billion to the low part-per-million levels and periods of from 0.5 to 72 h were investigated. Table I11 provides data for micrograms collected as a function of pg/(ppm.h) for bromodichloromethane. Linearity was obtained over the range tested for each of the compounds studied. For each compound, the permeation rate as a function of temperature increased in an approximately linear fashion with increasing temperature. Table IV contains information on the slope of the temperature effect and the percent change per “C for each compound. The percent change per degree was generally between 3% and 4% for each of the compounds over a temperature range from 0 to 30 “C.
LITERATURE CITED (1) (2) (3)
“Protectlon of Environment, US. Code of Federal Regulations”;1982; Voi. 40, Part 122. “Guidelines Establishing Test Procedures for the Analysis of Pollutants”; 44 FR 69464, Dec 3, 1979. Bellar, T. A.; Lichtenberg, J. J. J.-Am. Water Works Assoc. 1974,
66, 739-744. K.; Blanchard, R. D. Anal. Chem. 1984, 5 6 , 1621-1624. K.; Dasgupta, P. K.; Reiszner, K. D.; West, P. W. Envlron. Sci. Techno/. 1979, 73, 1090-1093. (6) West, P. W.; Reiszner, K. D. Am. I n d . Hyg. Assoc. J . 1978, 39, 645-650. (7) Reiszner, K. D.; West, P. W. Environ. Sci. Techno/. 1973, 7 , 526-532. (8) Hardy, J. K.; Strecker, D. T.; Savariar, C. P.; West, P. W. Am. Ind. Hyg.ASSOC. J . 1981, 42, 283-286.
Hardy, J. (5) Hardy, J.
(4)
Received for review April 12, 1985. Accepted June 19,1985. This work was supported by the donors of the Pertroleum Research Fund, administered by the American Chemical Society.
Two-Dimensional Enzyme Electrode Sensor for Glucose David A. Gough,* Joseph Y. Lucisano, and Pius H. S. Tse
Department of Applied Mechanics and Engineering Sciences, Bioengineering Group, University of California, S a n Diego, L a Jolla, California 92093
The enzyme electrode-type sensor holds promise as a tool for contlnuous monitorlng bf glucose Concentration In physlologic systems. Previous designs based on parallel dlffuslon of glucose and oxygen Into the enzyme-contalnlng membrane may, however, have certain dlsadvantages for In vivo appllcatlon. A novel sensor conflguratlon Is described In whlch oxygen dlffuses Into the membrane from two directions while glucose dlffuses from only one. Thls results in sensitivlty to glucose concentratlon over a wide range, even at very low oxygen concentratlons.
An electrochemical sensor based on the “enzyme electrode” principle was proposed years ago as a means of monitoring glucose concentration ( 1 , Z ) . A recent version of this sensor (3) operates by glucose and oxygen diffusing from the sample medium into a membrane that contains the immobilized enzymes glucose oxidase and catalase, where the following chemical reaction takes place: glucose
-
+ 1/202gluconic acid
(1)
Excess oxygen that is not consumed in this reaction is detected
0003-2700/65/0357-2351$01.50/0Q 1985 American Chemical Society
