ANALYTICAL SCIENCES MAY 2004, VOL. 20 2004 The Japan Society for Analytical Chemistry 865 Development of a Headspace GC/MS Analysis for Carbonyl Compounds (Aldehydes and Ketones) in Household Products after Derivatization with o-(2,3,4,5,6-pentafluorobenzyl)- hydroxylamine Naeko SUGAYA,* 1 Katsumi SAKURAI,* 1 Tomoo NAKAGAWA,* 1 Nobuhiko ONDA,* 2 Sukeo ONODERA,* 3 Masatoshi MORITA,* 4 and Masakatsu TEZUKA* 5 *1 Yokohama City Institute of Health, 1-2-17 Takigashira, Isogo-ku, Yokohama 235 0012, Japan *2 PerkinElmer Japan, 2-8-4 Kitasaiwai, Nishi-ku, Yokohama 220 0004, Japan *3 Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278 8510, Japan *4 National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba-shi, Ibaraki 305 8506, Japan *5 College of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi-shi, Chiba 274 8555, Japan Carbonyl compounds (aldehydes and ketones) are suspected to be among the chemical compounds responsible for Sick Building Syndrome and Multiple Chemical Sensitivities. A headspace gas chromatography/mass spectrometry (GC/MS) analysis for these compounds was developed using derivatization of the compounds into volatile derivatives with o- (2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBOA). For GC/MS detection, two ionization modes including electron impact ionization (EI) and negative chemical ionization (NCI) were compared. The NCI mode seemed to be better because of its higher selectivity and sensitivity. This headspace GC/MS (NCI mode) was employed as analysis for aldehydes and ketones in materials (fiber products, adhesives, and printed materials). Formaldehyde was detected in the range of N.D. (not detected) to 39 µg/g; acetaldehyde, N.D. to 4.1 µg/g; propionaldehyde, N.D. to 1.0 µg/g; n- butyraldehyde, N.D. to 0.10 µg/g; and acetone, N.D. to 3.1 µg/g in the samples analyzed. (Received February 18, 2004; Accepted April 1, 2004) Introduction Recently, Sick Building Syndrome and Multiple Chemical Sensitivities have become significant health issues. A wide range of chemicals are suspected to cause these problems, with aromatic hydrocarbons, alcohols, aldehydes, and ketones being detected in indoor air. 1,2 Among these chemicals, aldehydes, especially formaldehyde, have been widely detected in indoor air. The World Health Organization (WHO) has indicated that exposure to 0.08 ppm of formaldehyde in indoor air can cause serious health problems. 3 However, there are some reports that exposure at concentrations of less than 0.08 ppm increases allergic risks. 4,5 Thus, the need for highly sensitive analytical methods to detect formaldehyde in environmental samples is increasingly important. Another group of chemicals, ketones, are also widely used as solvents in adhesives, printing inks, and cosmetics, and are known to be mucous membrane stimulants. Furthermore, it is reported that methyl ethyl ketone may increase the neurotoxicity of other solvents. 6 A number of household products are considered to be the major source of these aldehydes and ketones. There have been several reports of analytical methods for detecting aldehydes and ketones in the air. These methods To whom correspondence should be addressed. E-mail: sugayanaeko@crocus.ocn.ne.jp involve derivatization with 2,4-dinitrohydrazone (2,4-DNPH), o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBOA), or 2- aminoethanethiol (cysteamine), with each derivative extracted by solvents, such as hexane, and then analyzed by GC, HPLC, or GC/MS. 7 11 However, there have been only limited reports of highly sensitive analysis of household products that are considered to be the source of these indoor aldehydes and ketones. Sugaya et al. reported on the microanalysis of aldehydes in water by headspace GC/MS. 12 On this basis, a rapid and sensitive analytical method was developed that involves the gas elution of aldehydes and ketones into water from materials, followed by derivatization by PFBOA, and headspace gas determination by GC/MS (NCI mode). The method applied for aldehydes (formaldehyde, acetaldehyde, propionaldehyde, isoand n-butyraldehyde) and ketones (acetone, methyl ethyl ketone (MEK), and methyl iso-butyl ketone (MIBK)) in household products is reported herein. Experimental Samples Twenty four samples of household products (fiber products, adhesives, and magazines) were purchased from retail outlets in Japan in 2003. These samples were stored in sealed plastic bags immediately after purchase to avoid possible volatilization and
866 ANALYTICAL SCIENCES MAY 2004, VOL. 20 Table 1 Retention time and SIM monitor ions of PFBOA aldoxime and ketoxime Compound R.T./min Electron ionization (EI) Quantitative ion Qualitative ion Negative chemical ionization (NCI) Quantitative ion Qualitative ion PFBOA formaldoxime 6.49 181 195, 225 181 205, 225 PFBOA acetaldoxime (syn) 8.56 181 209, 239 181 219, 239 PFBOA acetaldoxime (anti) 8.73 181 209, 239 181 219, 239 PFBOA propionaldoxime (syn) 10.37 181 236, 253 181 233, 253 PFBOA propionaldoxime (anti) 10.51 181 236, 253 181 233, 253 PFBOA iso-butyraldoxime (syn) 11.17 181 239,267 181 247, 267 PFBOA iso-butyraldoxime (anti) 11.21 181 239, 267 181 247, 267 PFBOA n-butyraldoxime (syn) 12.20 181 239, 267 181 247, 267 PFBOA n-butyraldoxime (anti) 12.33 181 239, 267 181 247, 267 PFBOA acetoneketoxime 9.95 181 223, 253 181 203, 233 Z-PFBOA MEKketoxime 11.56 181 250, 267 181 206, 247 E-PFBOA MEKketoxime 11.64 181 250, 267 181 206, 247 Z-PFBOA MIBKketoxime 13.85 181 253, 295 181 234, 275 E-PFBOA MIBKketoxime 14.00 181 253, 295 181 234, 275 Internal standard 4.74 174 95, 176 79 81 water. Instrument A headspace auto-sampler (HS40XL, PerkinElmer, Inc., Shelton, CT, USA) was connected to a GC/MS (quadruple mass spectrometer, TruboMass, PerkinElmer, Inc., Shelton, CT, USA). The capillary column used was a Supelco PTE-5 (Supelco, Bellefonte, PA, USA) of 30 m length 0.25 mm i.d. 0.25 mm membrane thickness. Fig. 1 In situ PFBOA derivatization in a headspace vial. contamination. The front and middle pages of magazines were analyzed separately. Reagents PFBOA was purchased from Hayashi Pure Chemical Inc. Ltd. (Osaka, Japan). Aldehyde standards (10000 mg/l formaldehyde, acetaldehyde, propionaldehyde, iso- and n-butyraldehyde) were purchased from Kanto Kagaku (Tokyo, Japan), and gradually diluted with methanol to make stock solutions. Acetone (pesticide analysis grade), MEK (reagent grade), and MIBK (reagent grade) were purchased from Kanto Kagaku (Tokyo, Japan), and diluted with methanol to 10000 mg/l solutions. A mixed ketone standard stock solution containing acetone (100 mg/l), MEK (100 mg/l) and MIBK (200 mg/l) was prepared by diluting the individual stock solutions with methanol. 4-Bromofluorobenzene (1000 mg/l) was purchased from Kanto Kagaku (Tokyo, Japan), and then diluted to 50 mg/l with methanol for use as the internal standard. Methanol (pesticide analysis grade) and sodium chloride (special grade) were purchased from Kanto Kagaku (Tokyo, Japan). Blank water Commercial bottled mineral water, minimally contaminated with aldehydes and ketones, was selected and used as the blank Sampling and GC/MS condition Vials were warmed to 60 C in the headspace auto-sampler. The sampling needle and transfer lines were set at 120 C and 180 C, respectively. Pressurized by helium for 1 min at 20 psi, the injection duration of the headspace was set at 0.08 min. The ionization voltage was set at 70 ev and the ion source temperature at 200 C (EI mode) or 150 C (NCI mode); isobutane (99.99%) was used for CI analysis. The column temperature was first programmed at 60 C (2 min), then at 7 C/min to 150 C, and finally at 20 C/min to 200 C. The monitored ions for the selected ion monitoring (SIM) and retention times of the compounds are summarized in Table 1. Preparation of standard solutions and sample solutions A standard solution was made by adding 10 ml of water, 1 µl of a standard stock solution, 1 µl of an internal standard, 0.6 ml of a PFBOA water solution (1 mg/ml), and 3 g of sodium chloride into a headspace vial, and then tightly sealed with a silicone rubber septum with PTFE, as shown in Fig. 1. 12 Sample solutions were made by adding 50 100 mg samples, 10 ml of water, 1 µl of an internal standard, 0.6 ml of a PFBOA water solution (1 mg/ml), and 3 g of sodium chloride into headspace vials, and then tightly sealed with a silicone rubber septa. Results and Discussion Reaction of aldehydes and ketones with PFBOA PFBOA derivatization makes compounds sufficiently volatile for GC analysis, because it contains five fluorine atoms. The condensation reaction (Fig. 2) produces derivatives (PFBOA aldoxime and PFBOA ketoxime), even at room temperature and
ANALYTICAL SCIENCES MAY 2004, VOL. 20 867 Fig. 2 Reaction of PFBOA with aldehydes (above) and ketones (below). Fig. 4 Effect of the reaction time on the PFBOA ketoxime yield at 60 C. Mode, EI; monitoring ion, m/z 181. 300, and 360 min and at 20, 40, and 60 C. The reaction was too slow at 20 and 40 C. The reaction seemed to reach equilibrium in 4 h at 60 C, as shown in Fig. 4. The EI mode was employed and m/z 181 was monitored for all ketoximes in this study. Each area of MEK and MIBK was remarkably smaller than that of acetone in Fig. 4, because the ion intensity of MEKketoxime and MIBKketoxime at m/z 181 was lower than that of acetoneketoxime by GC/MS (EI mode) and acetoneketoxime, which had a faster retention time in capillary GC analysis, and was detected more sensitively than the others. This condition was employed for subsequent experiments. Fig. 3 NCI mass chromatograms of PFBOA aldoximes (a) and ketoximes (b). 1, Formaldoxime; 2, PFBOA; 3, acetaldoxime (syn); 4, acetaldoxime (anti); 5, propionaldoxime (syn); 6, propionaldoxime (anti); 7, iso-butyraldoxime (syn); 8, iso-butyraldoxime (anti); 9, n- butyraldoxime (syn); 10, n-butyraldoxime (anti); a, acetoneketoxime; b, Z-MEKketoxime; c, E-MEKketoxime; d, Z-MIBKketoxime; e, E- MIBKketoxime. in water. The reactivity of the carbonyl group in aldehydes and ketones depends on its location within the molecule, particularly those alkyl groups adjacent to the carbonyl. In general, for alkyl groups, the carbonyl group reactivity increases as the size of the alkyl group decreases. 13 Compounds with nitrile (C=N) groups form with syn and anti isomer derivatives for all carbonyl compounds, except for formaldehyde (R 1 = H) and acetone (R 2 = R 3 = CH 3). The separation and confirmation of these isomers require capillary column GC analysis. Figure 3 shows the separation of a mixture of five aldoximes of aldehydes and a mixture of three aldoximes of aliphatic ketones by the headspace GC/MS (NCI mode). As can be seen in the mass chromatograms in Fig. 3, formaldehyde and acetone are detected as single peaks, whereas the other compounds are detected as two close peaks. 12,14 It is important to note that the syn and anti isomers of isobutyraldoxime are very close each other. Optimum reaction conditions for the condensation of PFBOA and ketones The reaction of PFBOA and ketones is known to be slower than that with aldehydes. 15 In this study, the optimum reaction condition was searched by changing at reaction times and temperatures, including the following: 30, 70, 130, 180, 240, Comparison between NCI and EI mass spectra of PFBOA ketoximes The mass spectra of EI were compared to that of NCI for PFBOA ketoximes (Figs. 5, 6). The EI mass spectra molecular ions, [M] +, were m/z 253 for acetoneketoxime, m/z 267 for MEKketoxime, and m/z 295 for MIBKketoxime. PFBOA derivatives showed a base fragment peak at m/z 181 [M ON=CH R] +. Acetoneketoxime was observed to have a fragment peak [M C 6F 5 CH 2] + at m/z 72, MEKketoxime at m/z 86, and MIBKketoxime at m/z 114. The NCI mass spectra had more simple fragmentation patterns compared with the EI mass spectra. The base fragment peak, [M ON=CH R], was at m/z 181, and the characteristic peaks of [M HF] were observed, such as acetoneketoxime at m/z 233, MEKketoxime at m/z 247 and MIBKketoxime at m/z 275. The NCI mass spectrum of PFBOA aldoxime has been reported 12 to typically consist of only a few ions: a molecular ion [M], an ion that has 20 mass units less than that of molecular ion [M HF], and the pentafluorobenzyl ion at m/z 181. Such spectra have a small number of fragment ions that are typical of aldehydes, and are therefore useful for compound detection. In this study, no molecular ion peak was observed in the NCI spectrum of PFBOA ketoxime, but the pentafluorobenzyl ion at m/z 181 was strongly detected compared to the EI mode. It was therefore determined to be useful for highly sensitive analysis. Calibration curves and detection limits for ketones Calibration curves for ketones using the headspace GC/MS (SIM) are shown in Fig. 7 (EI mode) and Fig. 8 (NCI mode). Calibration curves were calculated from peak areas using the internal standard. The total peak areas of all isomers were used with the exception of acetone. It is worth noting that acetone was detected even in blank water, and therefore the calibration curves did not go through the original point. Using EI, acetone had linear calibration curves within a range of 0.2 20 µg/l; MEK, 0.6 20 µg/l; and MIBK, 1.2 20
868 ANALYTICAL SCIENCES MAY 2004, VOL. 20 Fig. 7 Calibration curves of ketones (EI). (a) Acetone, (b) MEK, (c) MIBK. Fig. 5 EI mass spectra of PFBOA ketoximes. Fig. 8 Calibration curves of ketones (NCI). (a) Acetone, (b) MEK, (c) MIBK. Fig. 6 NCI mass spectra of PFBOA ketoximes. µg/l. Acetone, MEK and MIBK had good correlation coefficients (0.9990 0.9998). Using NCI, acetone and MEK had linear calibration curves within the range of 0.2 30 µg/l, and MIBK of 0.4 20 µg/l. The correlation coefficients were good (0.9989 0.9998). The determination limits and standard deviations of each compound given in Table 2 were defined according to Method for determination of tetra- through octa-chlorodibenzo-pdioxins, tetra- through octa-chlorodibenzofurans and coplanar polychlorobiphenyls in industrial water and waste water (JIS K0312). 16 The determination limits of ketones by headspace GC/MS (SIM) were acetone, 0.2 µg/l; MEK, 0.6 µg/l; MIBK, 1.2 µg/l, respectively, for the EI mode. However, the determination limits by the NCI mode were acetone, 0.2 µg/l; MEK, 0.2 µg/l; and MIBK, 0.4 µg/l, respectively. The NCI mode is more sensitive, but the determination limit for acetone is similar. This is because acetone was detected in blank water. It is possible to reduce the determination limit for the NCI mode if the blank level is reduced. Application to household products Because it is important to investigate the source of compounds with carbonyl groups in indoor air to specify the cause of health
ANALYTICAL SCIENCES MAY 2004, VOL. 20 869 Table 2 Determination limits and standard deviations of ketones (n = 6) Compound Determination limit Electron ionization (EI) Standard deviation RSD, % a Negative chemical ionization (NCI) Determination limit Standard deviation RSD, % a Acetone 0.2 0.0177 8.85 0.2 0.0113 5.65 MEK 0.6 0.0481 8.02 0.2 0.0182 9.11 MIBK 1.2 0.0614 5.12 0.4 0.0246 6.14 a. Relative standard deviation. Table 3 Ketone concentrations in household products No. Sample Material Acetone MEK MIBK Fig. 9 NCI mass fragmentograms of sample No. 12 (a) and sample No. 6 (b). 1, Formaldoxime; 2, PFBOA; 3, acetaldoxime (syn); 4, acetaldoxime (anti); 5, propionaldoxime (syn); 6, propionaldoxime (anti); 9, n-butyraldoxime (syn); 10, n-butyraldoxime (anti); a, acetoneketoxime. problems, such as Sick Building Syndrome and Multiple Chemical Sensitivities, an analytical application of household products was performed. Although household products contain various chemicals, a highly sensitive, high selectively headspace GC/MS (NCI mode) could remove interferences, and was applied to aldehyde and ketone quantitative analysis. The method uses a small amount of samples (50 100 mg), and can analyze up to the 0.01 µg/g level. Figure 9 shows the mass fragmetograms of aldehydes and ketones in household products. In Fig. 9, m/z 181 was monitored as a quantitative ion of aldehydes in a magazine (sample No. 12) and m/z 233 was monitored as a qualitative ion of acetone in an adhesive (sample No. 6). Ketones in household products Table 3 gives the results for the determination of ketones in household products. Acetone in the samples was detected within the level of N.D. 4.1 µg/g. However, MEK and MIBK were not detected in any of the samples examined. Aldehydes in household products Table 4 gives the results for the determination of aldehydes in household products. The formaldehyde contents in clothes and adhesives, among household products, are regulated in Japan in an effort to prevent skin damage from formaldehyde. 17 In the analyzed samples, formaldehyde was detected at the level of N.D. to 39 µg/g; acetaldehyde, N.D. to 4.1 µg/g; propionaldehyde, N.D. to 1.0 µg/g; and n-butyraldehyde, N.D. to 0.28 µg/g, while isobutyraldehyde was not detected. Formaldehyde was detected from most of the samples, and it was confirmed that various household products contain formaldehyde. In printed materials, it was found that a significant amount of aldehyde was present: formaldehyde, 0.93 11 µg/g; propionaldehyde, 0.05 1.0 µg/g; and n- butyraldehyde, N.D. 0.28 µg/g, respectively. Printed materials are thought to be sources of these indoor aldehydes. The source of formaldehyde in printed materials can be from both the ink and paper. The analysis of front pages of 1 Adhesive Starch N.D. N.D. N.D. 2 Adhesive Starch 0.21 N.D. N.D. 3 Adhesive Starch N.D. N.D. N.D. 4 Adhesive Acrylic adhesive, 0.08 N.D. N.D. 5 Adhesive Acrylic adhesive, 0.15 N.D. N.D. flavor, aloe extract 6 Adhesive Acrylic adhesive, 3.1 N.D. N.D. 7 Magazine Paper, ink N.D. N.D. N.D. 8 Magazine Paper, ink N.D. N.D. N.D. 9 Magazine Paper, ink N.D. N.D. N.D. 10 Magazine Paper, ink N.D. N.D. N.D. 11 Magazine Paper, ink N.D. N.D. N.D. 12 Magazine Paper, ink N.D. N.D. N.D. 13 Magazine Paper, ink 0.07 N.D. N.D. 14 Magazine Paper, ink N.D. N.D. N.D. 15 Magazine Paper, ink N.D. N.D. N.D. 16 Magazine Paper, ink N.D. N.D. N.D. 17 Magazine Paper, ink 0.30 N.D. N.D. 18 Magazine Paper, ink N.D. N.D. N.D. 19 Clothes Cotton (100%) N.D. N.D. N.D. 20 Clothes Cotton, nylon 0.04 N.D. N.D. 21 Clothes polyurethane Polyester (100%) 0.31 N.D. N.D. 22 Clothes Polyester (100%) N.D. N.D. N.D. 23 Clothes Cotton (100%) N.D. N.D. N.D. 24 Clothes Cotton (50%), polyester (50%) 0.03 N.D. N.D. Unit: µg/g. N.D.: Not detected. magazines showed formaldehyde at a level of 1.3 1.9 µg/g (mean of 1.6 µg/g), whereas the middle pages showed a level of 0.93 11 µg/g (mean of 6.02 µg/g). Conclusions We developed a rapid and sensitive microanalysis method for aldehydes and ketones in household products. The method includes headspace GC/MS with negative chemical ionization after derivatizing the carbonyl compounds with PFBOA, after eluting into water (60 C). The headspace GC/MS (NCI mode) that employs PFBOA is a highly sensitive analytical method that resists influences by interfering substances present in large quantities in samples. Consequently, this technique was
870 ANALYTICAL SCIENCES MAY 2004, VOL. 20 Table 4 Aldehyde concentrations in household products No. Sample Material FA AA PA iso-ba n-ba 1 Adhesive Starch, fungicides 0.38 0.07 N.D. N.D. N.D. 2 Adhesive Starch, 9.6 N.D. N.D. N.D. N.D. fungicides 3 Adhesive Starch 2.7 0.41 N.D. N.D. N.D. 4 Adhesive Acrylic 0.22 3.3 N.D. N.D. N.D. 5 Adhesive adhesive, Acrylic N.D. 1.8 N.D. N.D. N.D. adhesive, flavor, aloe extract 6 Adhesive Acrylic adhesive, 0.21 4.1 N.D. N.D. N.D. 7 Magazine Paper, ink 1.4 0.05 0.05 N.D. N.D. 8 Magazine Paper, ink 1.7 0.08 0.17 N.D. N.D. 9 Magazine Paper, ink 1.6 0.13 0.08 N.D. N.D. 10 Magazine Paper, ink 1.9 0.15 0.25 N.D. N.D. 11 Magazine Paper, ink 1.8 0.09 0.05 N.D. N.D. 12 Magazine Paper, ink 1.3 0.09 0.14 N.D. 0.28 13 Magazine Paper, ink 0.93 0.10 0.09 N.D. N.D. 14 Magazine Paper, ink 3.6 0.17 0.10 N.D. N.D. 15 Magazine Paper, ink 9.4 0.28 1.0 N.D. 0.10 16 Magazine Paper, ink 5.5 0.27 0.47 N.D. 0.08 17 Magazine Paper, ink 5.5 0.11 0.06 N.D. N.D. 18 Magazine Paper, ink 11 0.18 0.13 N.D. 0.10 19 Clothes Cotton (100%) 9.0 0.06 N.D. N.D. N.D. 20 Clothes Cotton, nylon 0.64 N.D. N.D. N.D. N.D. polyurethane 21 Clothes Polyester (100%) 0.09 0.05 N.D. N.D. N.D. 22 Clothes Polyester 26 0.07 N.D. N.D. N.D. (100%) 23 Clothes Cotton (100%) 30 0.09 N.D. N.D. N.D. 24 Clothes Cotton (50%), polyester (50%) 39 0.06 N.D. N.D. N.D. Unit: µg/g. N.D.: Not detected. FA, formaldehyde; AA, acetaldehyde; PA, propionaldehyde; iso-ba, iso-butyraldehyde; n-ba, n-butyraldehyde. expected to be widely applicable to the analysis of such materials as food and biological samples, as well as in the analysis of household products. References 1. Ministry of Health and Welfare, Japan, National survey of volatile organic compounds in the indoor environment (in Japanese), 1999, Ministry of Health and Welfare, Environmental Health Bureau, Planning Division, Environmental Chemical Safety, Japan. 2. J. Zheng, T. Tanaka, T. Tanaka, and Y. Kobayashi, J. Environ. Chem. (in Japanese), 2000, 10, 807. 3. World Health Organization, Air quality guidelines, 1999, World Health Organization (WHO), Geneva. 4. M. H. Garrett, M. A. Hooper, B. M. Hooper, P. R. Rayment, and M. J. Abramson, Allergy, 1999, 54, 330. 5. F. Wantke, C. M. Demmer, P. Tappler, M. Gotz, and R. Jarisch, Clin. Exp. Allergy, 1996, 26, 276. 6. M. Ikeda, in Industrial Poisoning Handbook, Enlarged Edition (in Japanese), ed. S. Goto, M. Ikeda, and I. Hara, 1994, Ishiyaku Publishers, Inc., Tokyo, 864. 7. K. Kuwata, M. Uebori, H. Yamasaki, Y. Kuge, and Y. Kiso, Anal. Chem., 1983, 55, 2013. 8. X. Zhou and K. Mopper, Environ. Sci. Technol., 1990, 24, 1482. 9. A. Yasuhara and T. Shibamoto, J. Assoc. Off. Anal. Chem., 1989, 72, 899. 10. Y. Mori, S. Setsuda, S. Goto, S. Onodera, S. Nakai, and H. Matsushita, J. Health Sci. (in Japanese), 1999, 45, 105. 11. J. A. Koziel, J. Noah, and J. Pawliszyn, Environ. Sci. Technol., 2001, 35, 1481. 12. N. Sugaya, T. Nakagawa, K. Sakurai, M. Morita, and S. Onodera, J. Health Sci., 2001, 47, 21. 13. S. Umezawa, in Yukikagaku I (Organic Chemistry I, in Japanese), 1961, Maruzen Co., Ltd., Tokyo, 160. 14. Y. Mori, K. Tsuji, S. Setsuda, S. Goto, S. Onodera, and H. Matsushita, Jpn. J. Toxicol. Environ. Health (in Japanese), 1996, 42, 500. 15. K. Kobayashi, M. Tanaka, and S. Kawai, J. Chromatogr., 1980, 187, 413. 16. JIS K0312, Method for determination of tetra- through octa-chlorodibenzo-p-dioxins, tetra- through octachlorodibenzofurans and coplanar polychlorobiphenyls in industrial water and waste water, 1999, Japanese Industrial Standards Committee, Tokyo. 17. Low for the Control of Household Products Containing Harmful Substances, Low No.112, 1973, Japan.