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(2) Fox, J. P.; Mason, K. K.; Duvall, J. J. Oil Shale Symp. Proc. 1979,12, 58-71. (3) Fruchter, J. S.; Wilkerson, C. L.; Evans, J. C.; Sanders, R. W. Enuiron. Sci. Technol. 1980. 11. 1374-1381. (4) Wildeman, T. R.; Meglen, R. R. Adu.’Chem. Ser. 1978, No. 170, 195-212. ( 5 ) Dale, L. S.; Fardy, J. J. Enuiron. Sci. Technol. 1984, 18, 887-889. (6) Patterson, J. H.; Ramsden, A. R.; Dale, L. S.; Fardy, J. J. Chem. Geol. 1986,55, 1-16. ( 7 ) Wilkerson, C. L. Fuel 1982, 61, 63-70. (8) Fruchter, J. S.; Wilkerson, C. L. In Oil Shale the Enuironmental Challenges; Petersen, K. K., Ed.; Colorado School of Mines: Golden, CO, 1981; pp 31-55. (9) Fox, J. P.; Hodgson, A. T.; Girvin, D. C. In Energy and Environmental Chemistry,Fossil Fuels;Keith, L. H., Ed.; Ann Arbor Science: Ann Arbor, MI, 1982; Vol. 1,pp 69-102. (10) Bertine, K. K.; Goldberg, E. D. Science (Washington,D.C.) 1971, 173, 233. (11) Atkins, A. R.; Fookes, C. J. R.; Muradian, A.; Stephenson, L. Fuel 1987,66, 392-395. (12) Sikonia, J. G. Presented a t the 47th Mid-Year Refining Meeting of the American Petroleum Institute, New York, May 1982.
(13) Hart, B. T. Aust. Water Resour. Counc. Tech. Pap. 1974, 7, 1-349. (14) Riley, K. W.; Saxby, J. D. Chem. Geol. 1982,37,265-275. (15) Ekstrom, A. J.; Fookes, C. J. R.; Hambley, T.; Miller, S. A.; Taylor, J. C. Nature (London)1983, 306, 173. (16) Ekstrom, A.; Loeh, H.; Dale, L. ACS Symp. Ser. 1983, No. 230,411-422. (17) Fish, R. H.; Tannous, R. S.; Walker, W.; Weiss, C. S.; Brinckman, F. E. J . Chem. SOC.,Chem. Commun. 1983, 490-492. (18) Fish, R. H. ACS Symp. Ser. 1983, No. 230, 423-432. (19) Brinckman, F. E.; Weiss, C. S.;Fish, R. H. In Chemical and Geochemical Aspects of Fossil Energy Extraction; Yen, T. F.; Kawahara, F. R. K.; Hertzberg, R., Eds.; Ann Arbor Science: Ann Arbor, MI, 1983; pp 197-214. (20) Fish, R. H.; Brinckman, F. E.; Jewett, K. L. Enuiron. Sci. Technol. 1982, 16,174-179. (21) Jaganathan, J.; Mohan, M. S.; Zingaro, R. A.; Irgolic, K. J. J. Trace Microprobe Tech. 1985, 3, 345-375. (22) Patterson, J. H.; Dale, L. S.; Fardy, J. J.; Ramsden, A. R. Fuel 1987,66,319-322. Received for review April 18, 1986. Revised manuscript received October 6, 1986. Accepted January 30, 1987.
NOTES A Diffusion Monitor To Measure Exposure to Passive Smoking S. Katharine Hammond*?+and Brian P. Leaderert Environmental Health Sciences Program, Department of Family and Community Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, and John 6.Pierce Foundation Laboratory and Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut 065 19 ~
~~
A simple monitor to measure personal exposure to environmental tobacco smoke (ETS) was developed. The monitor is based on passive diffusion of nicotine to a filter treated with sodium bisulfate. The nicotine is then extracted from the filter and analyzed by gas chromatography. The diffusion monitor was validated over 5-h periods in an environmental chamber under controlled conditions for a range of constant smoking and ventilation rates, which produced nicotine concentrations between 16 and 250 pg/m3 and total particle levels between 150 and 1500 pg/m3. The passive monitors sampled at 25 mL/min, which agreed with the theoretically calculated rate of 24 mL/min. The diffusion monitors were also tested and performed well under widely varying concentrations for periods of 3-7 days. The monitor can measure a wide range of ETS concentrations and should be useful to characterize exposure to ETS for epidemiologic and other studies. ~
~
~~~~
Concern about the health and comfort effects of passive smoking and the large population of nonsmokers exposed to environmental tobacco smoke (ETS) have contributed to the need to develop methods to measure exposure to ETS. Epidemiologic studies of the possible adverse health effects of passive smoking are hampered by the lack of an Massachusetts Medical School. Yale University School of Medicine.
t University of f
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accurate measure of exposure. Environmental tobacco smoke is an aged mixture of sidestream smoke, that which is emitted directly from the cigarette into the environment, exhaled mainstream smoke, and gases that diffuse through the cigarette paper during smoking. ETS is a complex mixture of thousands of compounds in both the particulate and gas phases. Various proxies, or markers, for ETS have been used by investigators. These include particles (1-4), carbon monoxide (5), nitrogen oxides (3),acrolein (6),and nitrosamines (7). These markers are generally of only limited use because they either are not unique to tobacco, are not present in sufficient quantities to be measured in low ETS levels, or cannot be measured easily and inexpensively. By contrast, generally the only significant environmental source of nicotine is cigarette smoke. Nicotine is present in all cigarette smoke and is a major constituent in the smoke so that environmental concentrations are at easily measured levels even for low smoking rates. We recently reported a method to sample personal exposure to or indoor concentration of nicotine as a marker for ETS (8). This method, “active” sampling, employs a sampling pump, which draws air through a filter cassette. The cassette contains two filters in series: the first collects particles, and the second is treated with sodium bisulfate to collect vapor-phase nicotine. The nicotine is then desorbed from the filters and analyzed by gas chromatography for total nicotine.
0013-936X107/0921-0494$01.50/0
0 1907 American Chemical Society
A
Filter cassette
Sodium blsulfote treated filter Windscreen NucleoPore
Q ? Passive Monlitor f o r Nicotine in the Air
Figure 1. Diagram of passive monitor to sample nicotine in the air.
Recent studies indicate that nicotine in aged environmental tobacco smoke is prescnt predominantly in the vapor phase (8-20). The predominance of nicotine in the vapor phase of ETS (>go%) should then permit the development of a passive monitor to sample nicotine in the air as a measure of environmental tobacco smoke concentration. This is a preliminary note to report our initial results in designing a passive monitor on the basis of diffusion of nicotine.
Experimental Section Passive Monitor Design. The passive monitor itself is constructed from a modified 37 mm diameter polystyrene air sampling cassette (Figure 1). An alligator clip is riveted to the bottom of the cassette so the monitor can be attached to a shirt collar or otherwise placed conveniently. A support pad is placed into the bottom of the cassette and then a treated filter. The treated filter is a Teflon-coated glass fiber filter (Emfab TX4OHI2OWW, Pallflex Corp., Putnam, CT) that has been treated by saturating it with an aqueous solution of 4% sodium bisulfate and 5% ethanol and allowing the filter to dry. The filter is held in place by the windscreen, a polystyrene spacer whose top lip had been removed and onto which a Nucleopore filter (l0-wm pore) has been glued. Several windscreen designs were tested to ensure that orientation to air currents did not affect mass transfer to the treated filter. During transport or storage, the windscreen is replaced by a standard closed cassette half. Sampling Rate. The sampling rate can be calculated (22) from sampling rate = mass collected = -D A (1) (concn)(time) L where D = diffusion coefficient, A = cross-sectional area of sampler, and L = length of sampler (distance between windscreen and treated filter). For this sampler, A = 8.11 cm2,L = 1.17 cm, and D = 0.060 cm2/s10,with a resulting theoretical sampling rate equal to 25 mL/min. Empirical Sampling Rate. The diffusion-based monitors were tested in an environmental chamber under controlled conditions. The first set of tests were designed to establish an empirical sampling rate under constant smoking and ventilation rates and the second set to determine how well the samplers worked under conditions of varying concentrations and over several days. Experiments were conducted in an all-aluminum environmental chamber with a total volume of 34 m3. As described previously (8) the temperature, humidity, ventilation, and mixing in the chamber were all carefully controlled. The fresh air ventilation rate for all experiments was varied in combination with smoking rates to achieve a range of concentrations of nicotine and respirable suspendend particles associated with ETS. A recirculation
Day Figure 2. Experimental design. The concentration of total particulate matter (TPM) from environmental tobacco smoke is shown for each day. The letters refer to sampling sets, each of which contained 10 passive monitors. A, are the single smoking session sample sets, which sampled during constant smoking and ventilation rates for 4-5 h. B, are the 3- and e d a y sample sets, and C is the week-long sample set. These multipleday sets were left in the chamber through varying TPM levels.
rate of approximately 20 air changes/h was used to ensure near ideal mixing, and thus prevent any horizontal concentration gradient of the generated air contaminants in the chamber. The chamber was maintained at a temperature of 23 “C and a relative humidity of 50%. During all experiments, two to four smokers, depending on the smoking rate, occupied the test chamber. They smoked cigarettes serially at prescribed rates, varying from two to eight cigarettes/h, over a period of 5 h. Each cigarette was smoked for 7.5 min. The occupants smoked the same brand of cigarette for all experiments, a leading filter cigarette rated at 17 mg of tar and 1 mg of nicotine (mainstream smoke) by the Federal Trade Commission. During each sampling session, three pumps sampled the air at 1.7 L/min and collected both particles and nicotine as described previously (8). Briefly, two filters were contained in a single cassette: the first was weighed before and after sampling to determine the particle concentration; the second was treated with sodium bisulfate as described above. These “active” samples were used to determine the true concentration of nicotine and particles in the chamber during the experiments. In addition, 30 passive monitors were in the chamber during each of the five smoking sessions: 10 monitors sampled only during each of the five constant smoking and ventilation conditions sessions and were used to determine the empirical sampling rate, 10 monitors sampled for each of the two 3-4-day periods, and 10 monitors sampled for a full week (Figure 2). The passive monitors were placed perpendicular to the recirculating airflow in the chamber, which was 10 cm/s. All active and passive monitors were placed on one side of the chamber, at least 6 ft from the nearest smoker. At the end of each smoking session, the chamber was flushed with high rates of ventilation air to remove cigarette smoke quickly. Five different concentrations of suspended particles and nicotine were achieved during the five smoking sessions. The filters were analyzed as described previously (8). Briefly, the collected nicotine and bisulfate were desorbed in water, the pH was adjusted with 10 N sodium hydroxide, and the neutral nicotine molecule was concentrated into 250 pL of heptane by liquidlliquid extraction. An aliquot of the heptane solution was injected into a HewlettEnviron. Sci. Technol., Vol. 21, No. 5, 1987
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L
2
Table I. Comparison of Short-Term and Long-Term Passively Collected Nicotine Samples
*,O[ 18
multiple-day samples sample hours nicotine set” sampled collected pgb
1.41
-
n
B1 B2
101
C m = 0.0014 m3/hr :24 ml/min
71 96 167
2.0 (0.16) 1.1 (0.16) 2.4 (0.61)
corresponding single smoking session samples total nicotine sample seta collected, pgb
+ A, + A, + AS A1 + A2 + A3 +
A, A4
2.0 (0.48) 0.85 (0.14) 2.8 (0.50)
A4 + A5
See Figure 2. Mean (standard deviation). r :0.9948
[Nicotine] x Number of Hours Figure 3. Empirical sampling rate determined from data collected during constant smoking and ventilation rates, sample sets A,, in Figure 2. The micrograms of nicotine collected by the passive monitor is plotted against the concentration of nicotine, as determined by the active nicotine samplers previously validated, times the sampllng duration. The slope of the line is the sampling rate of the passive monitors. Error bars are one standard deviation.
Packard 5890 gas chromatograph with nitrogen-selective detection for quantitation of the nicotine.
Results Empirical Sampling Rate. Five sets of 10 passive monitors each (A, in Figure 2) were tested for 4-5 h at five concentrations of ETS under conditions of constant smoking and ventilation. The concentrations of ETS tested ranged from approximately 150 to 1500 pg/m3 total particulate mass. Figure 3 plots the micrograms of nicotine collected by the passive monitors during each test against the nicotine concentration (as determined by the active samplers) times the number of hours the passive monitors were exposed to cigarette smoke. The plot is linear over the range tested, with a correlation coefficient of 0.995. The slope of this plot indicates the empirical sampling rate is 24 mL/min. Extended Sampling over Varying Concentrations. In addition to the 5-h steady-state tests, the passive samplers were tested for 3 days, 4 days, and 1 week under varying concentrations of ETS-generated total particulate mass (Bl, B2, and C, respectively, in Figure 2), so any possible losses by off-gassing during sampling of low concentrations over longer periods of time could be seen. The several-day and week-long samples were collected over variable concentrations, including long periods with levels at or near zero (e.g., overnight), which more closely resemble true conditions in field studies. Table I compares the amount of nicotine collected by the single smoking session passive samples to that collected by the several-day passive monitors that sampled over the same periods. Discussion The experimentally determined sampling rate of the passive monitor for nicotine in air determined in these experiments,24 mL/min, agreed well with the theoretically calculated 25 mL/min. The passive monitor sampled as predicted over a wide range of exposures to aged ETS, from approximately 150 to 1500 pg/m3 environmental tobacco smoke particulate mass. When the sampler was exposed to intermittent and varying concentrations of ETS over several days (Figure 2), a condition which simulates those found in the “real world”, the passive monitors 496
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collected the same amount of nicotine as the smoking session samplers that were exposed for only the actual smoking periods, 4-5 h each. The concentrations of ETS tested in these experiments include those most commonly encountered by the general public, those associated with approximately 150-1500 pg/m3 tobacco smoke particles, over typical exposure time periods of a few hours ( 4 ) . The passive monitors were able to quantitate accurately nicotine concentrations as low as 16 pg/m3 (2.4 ppb) during a 5-h exposure and should be sensitive enough to measure nicotine levels associated with low smoking occupancy rates over a period of a day or less. Theoretically, the passive monitor can collect 100 pg of nicotine while maintaining a 100-fold excess sodium bisulfate. This level would be associated with exposure to over 4000 pg/m3 suspended particles from ETS for a full week, conditions which would not be experienced in the normal indoor environments. Some of the sample sets contained a large variability, particularly at the high concentrations. This may be due to several factors; for example, the pump flow rates for the active samplers may have differed slightly, the construction and assembly of the passive monitors might lead to variations in the dimensions of the samplers and so affect sampling rate, and nonuniform concentration in the chamber might have resulted in exposure to different concentrations of ETS and nicotine. We will be continuing to examine the causes of the large variation in some of these samples and to see if better mixing in the chamber and longer sampling times improve the precision. In other experiments, we are continuing to improve the design of the sampler, both the holder and the type of sorbent tested, and to assess potential nicotine loss to the surfaces of the samplers. We will be examining the passive monitor under a wider range of concentrations and sampling times. We will also be conducting field tests of the passive monitor. The passive monitor described here can measure exposure to low levels of airborne nicotine as a proxy for environmental tobacco smoke. Under the controlled conditions in the environmental chamber, a reproducible relationship was found between the concentrations of nicotine and the concentrations of suspended particles, approximately 10 pg of particles/pg of nicotine (8). However, important research issues remain. If nicotine is to serve as a proxy for ETS and its constituents, we must establish the environmental relationships between nicotine and other ETS constituents, such as suspended particles, N-nitrosodimethylamine, and acrolein, with emphasis on those compounds implicated in adverse health or comfort effects. Such important relationships include emission rates and rates of removal by surfaces or chemical transformation. These must be determined first under controlled conditions and then in typical indoor environments. Registry No. NaHSO,, 7681-38-1; nicotine, 54-11-5.
Envlron. Sci. Technol. 1987, 21, 497-500
M. Atmos. Environ. 1987,21, 457-461. (9) Eudy, L. W.; Thome, F. A.; Heavnre D. L.; Green, C. R.; Ingebrethson, B. J. Presented at the 39th Tobacco Chemists’ Research Conference, Montreal, Canada, Oct. 1985. (10) Eatough, D. J.; Benner, C.; Mooney, R. L.; Bartholomew, D.; Steiner, D. S.; Hansen, L. D.; Lamb, J. D.; Lewis, E. A.; Eatough, N. L. Abstracts of Papers, 19th Annual Meeting of the Air Pollution Control Association, Minneapolis, MN, June 1986; Air Pollution Control Association: Pittsburgh, PA, 1986; paper 86-68.5. (11) Palmes, E. D.; Burton, R. M.; Ravishankar, K.; Solomon, J. J. Am. Znd. Hyg. Assoc. J. 1986, 47, 418-420.
Literature Cited (1) Repace, J. L.; Lowrey, A. H. Science (Washington, D.C.) 1980,208, 464-472. (2) Spengler, J. D.; Treitman, R. D.; Tosteson, T. D.; Mage, D. T.; Soczek, M. L. Environ. Sci. Technol. 1985, 19, 700-707. (3) Weber, A,; Fischer, T. Znt. Arch. Occup. Environ. Health 1980,47, 209-221. (4) Repace, J. L.; Lowrey, A. H. Environ. Int. 1985,11, 3-22. (5) Sebben, J.; Pimm, P.; Shephard, R. J. Arch. Enuiron. Health 1977, 32, 53-58. (6) Badre, R.; Guillerme, R.; Abram, N.; Bourdin, M.; Dumas, C. Ann. Pharm. Fr. 1978,36,443-452. (7) Brunnemann, K. D.; Hoffmann, D. ZARC Sci. Publ. 1978, 19, 343-356. (8) Hammond, S. K.; Leaderer, B. P.; Roche, A. C.; Schenker,
Received for review September 23,1986. Accepted January 12, 1987.
I-Methylperimidine as a Solid Monitoring Reagent for Nitrogen Dioxidet Jack L. Lambert,” Eric L. Trump, and Joseph V. Pauksteils Department of Chemistry, Kansas State University, Manhattan, Kansas 66506
1-Methylperimidine on a solid support such as filter paper, with calcium chloride ag a humectant, serves as a stable, sensitive, and selective monitoring reagent for nitrogen dioxide in air. The reagent is intended for use with visual color comparison standards relating response of the reagent to concentration of nitrogen dioxide with constant time of exposure. Studies were made of the reagent response to concentration at constant exposure time and to time of exposure at constant concentration. The effects of relative humidity in the reagent storage container and in the test atmospheres were investigated. No interference was observed from ozone, chlorine, bromine, hydrogen sulfide, sulfur dioxide, carbon monoxide, or carbon dioxide.
Introduction Following the development of a solid, dry tin(I1)-diphenylcarbazide reagent responsive to both ozone and nitrogen dioxide (1,2),the strong oxidants of concern as atmospheric pollutants, studies were made to prepare new reagents specific for each of these oxidants. A number of lJ8-diaminonaphthalene derivatives were synthesized following an observation that Proton Sponge, l&bis(dimethy1amino)naphthalene(Aldrich),produced a color with small concentrations of nitrogen dioxide. This compound, however, did not respond to nitrogen dioxide once it was protonated, which would severely limit its usefulness. 1,8-Diaminonaphthalene reacted readily with nitrogen dioxide but it is too subject to oxidation by atmospheric oxygen to be of use as a reagent. This study involved the synthesis and reactions of perimidine and five of its derivatives prepared by methods (or modifications thereof) described in the literature and quantitative studies of the reaction of 1-methylperimidine with nitrogen dioxide. Experimental Section Table I summarizes the solubility characteristics and color responses to nitrogen dioxide of perimidine and the five derivatives synthesized. On the basis of these observations, l-methyl-2-(dimethylamino)perimidineand This paper was presented at the 190th National Meeting of the American Chemical Society, Chicago, IL, Sept. 8-13,1985, as CHAS 11. 0013-936X/87/0921-0497$01.50/0
H
a
CHJN/c*y
/
30-40% G C H 3 * yield
H NayNc*V
a
2-phenylperimidine were eliminated from further consideration because visual detection of the color changes were difficult. Perimidine was eliminated because of its gradual darkening over a period of a few hours exposure to air. 1-Acetylperimidine was eliminated because its color response was considerably less sensitive than those of 1methyl- and 2-methylperimidine. 2-Methylperimidinewas eliminated from consideration after the humectant (calcium chloride) was found to discolor the compound and destroy its reactivity. Only 1-methylperimidine was unaffected by atmospheric oxygen and the presence of the humectant, had the desired degree of sensitivity for nitrogen dioxide, and did not react with ozone. Preparation of 1-Methylperimidine (Scheme I). 1,B-Diaminonaphthalene(Aldrich) was obtained as a discolored product and was purified by one or more recrystallizations from a 1:l water-ethanol mixture. Further decolorization, if needed, was accomplished by heating an ethanol solution of the compound with a small amount of decolorizing carbon and filtering before another recrystallization step. The white product should be used immediately. Brown and Evans (3) suggested refluxing l,t)-diaminonaphthalene with formamidine acetate in ethanol but gave no details. The procedure worked out in this laboratory was to dissolve 15.8 g (0.100 mol) of recently purified 1,B-diaminonaphthalene in 400 mL of ethanol in a 1-L round-bottom flask, add 12.0 g (0.115 mol) of formamidine
0 1987 American Chemlcal SocietY
Environ. Sci. Technol., Vol. 21, No. 5, 1987 497
