Non-Metals
143
determined include trichloroethane, tetrachloroethylene, chloroform, and carbon tetrachloride [410,411], and 1,1,1 trichloroethane, trichloroethylene, perchloroethylene, 1,1,1,2 tetrachloroethane, 1,1,2,2 tetrachloroethane, pentachloroethane, hexachloroethane, pentachlorobutadiene, hexachlorobutadiene, chloroform, and carbon
tetrachloride [412-415].
Hiatt [416] has described a gas chromatography-mass spectrometry system for the
determination of a wide range of volatiles, including haloparaffins, in vacuum distillates of fish samples. Linde et al. [398] determined organohalogen compounds, as
halogen, in fish samples. The samples were steam distilled with cyclohexane for
halogen - containing non-polar compounds, and hexane extracts of oils from all
species were treated with concentrated sulphuric acid. Total amounts of halogens in
the original oils, in the volatile compounds in the cyclohexane distillate, and in the
sulphuric acid-treated hexane extracts were determined by neutron activation analysis. The total level of organic chlorine ranged from 30 to 240 ppm: 2-10 % of the
chlorinated compounds were volatile, and from 5 to 50 % of the chlorinated compounds remained after acid treatment. This chloride exceeded chlorine in polychlorinated biphenyl by a factor of 1.5 to 5, and most of the chlorine in untreated and
acid-treated lipids could not be accounted for as known compounds.
7.3.5
Ch/oropheno/s
Stark [417] has described a gas chromatograph method for the determination of
pentachlorophenol as the trimethyl silylether in amounts down to 0.5 mg kg-I in fish.
Rudling [418] determined pentachlorophenol in fish and water by an electron capture
gas chromatographic method. In this method, a sample of fish tissue (1 g) in water is
transferred to a centrifuge tube with 5 ml water, 1 ml6 moll-I sulphuric acid and 5 ml
1 : 5 isopropyl alcohol-hexane. The tube is centrifuged and cooled in ethanol-solid
carbon dioxide. The organic layer is decanted and extracted with 0.1 moll-I Na 2 B 4 0 7 •
Hexane (0.5 ml) and fresh acetylation reagent (pyridine (2 ml) plus acetic anhydride
(0.8 ml» (40~) are added to the combined aqueous extracts. The hexane phase is
analysed by gas chromatography on a glass column (1 m x 1.5 mm) packed with 5 %
of QF-l on Varaport 30 (100 to 120-mesh).
Renberg [419] has used an ion-exchange technique for the determination of chlorophenols and phenoxyacetic acid herbicides in fish tissue. The sample (5 g) is homogenized in a mixture of hexane and acetone (5 + 10 ml). The liquid is dropped into a
separatory funnel containing 1.0 moll-I hydrochloric acid (5 ml). The funnel is shaken
and the upper phase transferred into a centrifuge tube. Sodium sulphate (100-300 mg)
is added to bind any water present. After centrifugation, the extract is transferred into a
weighed flask, the sodium sulphate is rinsed with diethylether (2 ml), and the solvents
gently evaporated on a water bath in a nitrogen stream. The flask is reweighed and the
fat content calculated; the fat is then dissolved in benzene (about 1 ml per 25 mg fat is
used). After treatment with ion exchange resin, the chlorophenols in the extract are
converted to their methyl ethers using diazomethane and determined by gas chromatography. Detection limits for a 10 g fish sample are 0.1 to Illg kg-I.
Hoben et al. [420] has described a gas chromatographic technique for determining
143
determined include trichloroethane, tetrachloroethylene, chloroform, and carbon tetrachloride [410,411], and 1,1,1 trichloroethane, trichloroethylene, perchloroethylene, 1,1,1,2 tetrachloroethane, 1,1,2,2 tetrachloroethane, pentachloroethane, hexachloroethane, pentachlorobutadiene, hexachlorobutadiene, chloroform, and carbon
tetrachloride [412-415].
Hiatt [416] has described a gas chromatography-mass spectrometry system for the
determination of a wide range of volatiles, including haloparaffins, in vacuum distillates of fish samples. Linde et al. [398] determined organohalogen compounds, as
halogen, in fish samples. The samples were steam distilled with cyclohexane for
halogen - containing non-polar compounds, and hexane extracts of oils from all
species were treated with concentrated sulphuric acid. Total amounts of halogens in
the original oils, in the volatile compounds in the cyclohexane distillate, and in the
sulphuric acid-treated hexane extracts were determined by neutron activation analysis. The total level of organic chlorine ranged from 30 to 240 ppm: 2-10 % of the
chlorinated compounds were volatile, and from 5 to 50 % of the chlorinated compounds remained after acid treatment. This chloride exceeded chlorine in polychlorinated biphenyl by a factor of 1.5 to 5, and most of the chlorine in untreated and
acid-treated lipids could not be accounted for as known compounds.
7.3.5
Ch/oropheno/s
Stark [417] has described a gas chromatograph method for the determination of
pentachlorophenol as the trimethyl silylether in amounts down to 0.5 mg kg-I in fish.
Rudling [418] determined pentachlorophenol in fish and water by an electron capture
gas chromatographic method. In this method, a sample of fish tissue (1 g) in water is
transferred to a centrifuge tube with 5 ml water, 1 ml6 moll-I sulphuric acid and 5 ml
1 : 5 isopropyl alcohol-hexane. The tube is centrifuged and cooled in ethanol-solid
carbon dioxide. The organic layer is decanted and extracted with 0.1 moll-I Na 2 B 4 0 7 •
Hexane (0.5 ml) and fresh acetylation reagent (pyridine (2 ml) plus acetic anhydride
(0.8 ml» (40~) are added to the combined aqueous extracts. The hexane phase is
analysed by gas chromatography on a glass column (1 m x 1.5 mm) packed with 5 %
of QF-l on Varaport 30 (100 to 120-mesh).
Renberg [419] has used an ion-exchange technique for the determination of chlorophenols and phenoxyacetic acid herbicides in fish tissue. The sample (5 g) is homogenized in a mixture of hexane and acetone (5 + 10 ml). The liquid is dropped into a
separatory funnel containing 1.0 moll-I hydrochloric acid (5 ml). The funnel is shaken
and the upper phase transferred into a centrifuge tube. Sodium sulphate (100-300 mg)
is added to bind any water present. After centrifugation, the extract is transferred into a
weighed flask, the sodium sulphate is rinsed with diethylether (2 ml), and the solvents
gently evaporated on a water bath in a nitrogen stream. The flask is reweighed and the
fat content calculated; the fat is then dissolved in benzene (about 1 ml per 25 mg fat is
used). After treatment with ion exchange resin, the chlorophenols in the extract are
converted to their methyl ethers using diazomethane and determined by gas chromatography. Detection limits for a 10 g fish sample are 0.1 to Illg kg-I.
Hoben et al. [420] has described a gas chromatographic technique for determining