160
Fish
pherol isomers. The four tocopherols were completely separated during 15 min on a
5 ~ silica gel column with a silanized stationary phase. Fluorescence detection, with
excitation at 206 nm and measurement at 340 nm, permitted recoveries averaging
95 % from spiked samples, based on measurement of the peak areas.
7.3.23
Eulan WA (Polychloro-2-(chloro methyl sulphonamido) diphenylethers)
Wells and Cowan [488] described a gas liquid chromatographic method for determining
this mothproofing agent in fish tissue down to 0.005 mg kg-I, in which Eulan was
extractively methylated using tetrabutylammonium ion, which forms ion pairs with
sulphonamide at pH 10-12. This ion-pair was subsequently back-extracted into the
organic phase and methylated using methyl iodide. The methyl derivatives of the Eulan
were quantified by gas liquid chromatography using electron-capture detection.
The coefficient of variation (p > 0.05) for perch liver was 4.82 mg kg-I ± 5.6 % for
between-batch extractions.
To prepare the fish digest,S g of fish tissue is ground with sufficient anhydrous
sodium sulphate to obtain a free-flowing powder. The sample is then extracted for 2 h
with 100 ml hexane with a Soxhlet extractor. The extract is then passed down a
column containing acidic and basic alumina and eluted with hexane to remove
chlorinated insecticides, then with diethyl ether-glacial acetic acid to remove Eulan.
Addition of tetrabutyl ammonium hydroxide and methyl iodide to the second extract
methylates the Eulan ready for gas chromatographic analysis.
Concentrations of Eulan were determined in perch muscle and liver, with coefficients of variation of 38 % and 5.6 % respectively at the 0.2 and 4.8 mg kg-I levels.
7.3.24
Neutral Priority Pollutants
The extraction procedure [316] utilizing sonication with acetonitrile and clean-up
using aminopropyl and/ or C-18 bonded silica phases prior to gas chromatography,
discussed under priority pollutants in sediments in Sec. 4.4.11, has been applied to the
analysis of fish extracts. Using this procedure, the following values were obtained for
chlorinated insecticides and polychlorobiphenyls in a range of Environmental Protection Agency Reference fish samples:
found
nominal
mg kg-I
DDE
18.6 ± 2.7
20.0 ± 1.0
DDD
6.8 ± 2.7
8.0 ± 0.4
DDT
4.2 ±l.l
7.5 ± 0.3
PCB1254
3.12 ± 1.32
2.2 ± 0.08
Analytical recoveries from fish were variable, ranging from 7 % (naphthalene) to
60-70 % (isopherone, fluorene, hexachlorobenzene, anthracene, pyrene, dimethyl
phthalate, diethyl phthalate, di-n-butyl phthalate, n-butyl benzylphthalate, bis (2ethylhexyl) phthalate, and n-octyl phthalate. Crysene was exceptional in giving a
recovery of 76 %.
Fish
pherol isomers. The four tocopherols were completely separated during 15 min on a
5 ~ silica gel column with a silanized stationary phase. Fluorescence detection, with
excitation at 206 nm and measurement at 340 nm, permitted recoveries averaging
95 % from spiked samples, based on measurement of the peak areas.
7.3.23
Eulan WA (Polychloro-2-(chloro methyl sulphonamido) diphenylethers)
Wells and Cowan [488] described a gas liquid chromatographic method for determining
this mothproofing agent in fish tissue down to 0.005 mg kg-I, in which Eulan was
extractively methylated using tetrabutylammonium ion, which forms ion pairs with
sulphonamide at pH 10-12. This ion-pair was subsequently back-extracted into the
organic phase and methylated using methyl iodide. The methyl derivatives of the Eulan
were quantified by gas liquid chromatography using electron-capture detection.
The coefficient of variation (p > 0.05) for perch liver was 4.82 mg kg-I ± 5.6 % for
between-batch extractions.
To prepare the fish digest,S g of fish tissue is ground with sufficient anhydrous
sodium sulphate to obtain a free-flowing powder. The sample is then extracted for 2 h
with 100 ml hexane with a Soxhlet extractor. The extract is then passed down a
column containing acidic and basic alumina and eluted with hexane to remove
chlorinated insecticides, then with diethyl ether-glacial acetic acid to remove Eulan.
Addition of tetrabutyl ammonium hydroxide and methyl iodide to the second extract
methylates the Eulan ready for gas chromatographic analysis.
Concentrations of Eulan were determined in perch muscle and liver, with coefficients of variation of 38 % and 5.6 % respectively at the 0.2 and 4.8 mg kg-I levels.
7.3.24
Neutral Priority Pollutants
The extraction procedure [316] utilizing sonication with acetonitrile and clean-up
using aminopropyl and/ or C-18 bonded silica phases prior to gas chromatography,
discussed under priority pollutants in sediments in Sec. 4.4.11, has been applied to the
analysis of fish extracts. Using this procedure, the following values were obtained for
chlorinated insecticides and polychlorobiphenyls in a range of Environmental Protection Agency Reference fish samples:
found
nominal
mg kg-I
DDE
18.6 ± 2.7
20.0 ± 1.0
DDD
6.8 ± 2.7
8.0 ± 0.4
DDT
4.2 ±l.l
7.5 ± 0.3
PCB1254
3.12 ± 1.32
2.2 ± 0.08
Analytical recoveries from fish were variable, ranging from 7 % (naphthalene) to
60-70 % (isopherone, fluorene, hexachlorobenzene, anthracene, pyrene, dimethyl
phthalate, diethyl phthalate, di-n-butyl phthalate, n-butyl benzylphthalate, bis (2ethylhexyl) phthalate, and n-octyl phthalate. Crysene was exceptional in giving a
recovery of 76 %.