Organics
235
metabolism. The method can therefore be used to determine the threshold concentration of toxic substances for aquatic plants.
10.4
Organics
70.4.7
Hydrocarbons
Law et al. [688] have described procedures for the determination of hydrocarbons
(especially petroleum hydrocarbon residues from oil spills) in marine biota and
related environmental samples. Basic procedures for sample collection, extraction,
and cleanup are outlined, together with the methodology for fluorescence analysis.
70.4.2
Chlorinated Insecticides
Sackmauereva et al. [677, 678] have described the method, given below, for the
determination of chlorinated insecticides (BHC isomers, DDE, DDT, and hexachlorobenzene) in water weeds. In this method, a weighed portion of sample is dried at room
temperature and homogenized. From the pulverized sample, 20 g are taken and
extracted with petroleum ether in a Soxhlet apparatus for 12 h. The concentrated
extract is purified from coextracts on a Florisil filled column activated by heating at
120°C for 48 h with addition of 5 % water to the cooled column. Insecticides are
eluted from the column with 15 % dichloromethane in petroleum ether. The eluate is
concentrated to a volume of 1 ml and analysed by gas chromatography [679-683].
The following chlorinated insecticides can be determined in amounts down to the
concentrations stipulated below.
a-BHC
[}-BHC
y-BHC
&-BHC
p,p'-DDE
o,p'-DDT
p,p'-DDD
p,p'-DDT
0.15 mg kg- 1
0.75 mg kg- 1
0.2 mg kg- 1
0.15 mg kg- 1
0.45 mg kg- 1
0.5 mg kg- 1
1.5 mg kg- 1
1.5 mg kg- 1
Sackmauereva et al. [677] used thin layer chromatography on silica plates to confirm
the identity of chlorinated insecticides previously identified by gas chromatography.
The compounds can be separated by single or repeated one-dimensional development
in n-heptane or in n-heptane containing 0.3 % ethanol. The plate is dried at 65 °c for
10 min and detected by spraying with a solution of silver nitrate plus 2 phenoxyethanol [684, 685]. Thereafter the plate was dried at 65 °c for 10 min and illuminated with
an ultraviolet light (A = 254 nm) until spots representing the smallest amounts of
standards were visible (10-15 min).
Using the gas chromatography methods, Sackmauereva [677] obtained from spiked
samples the four BHC isomers at 93-103.5 % recovery. Both DDT and DDE were
235
metabolism. The method can therefore be used to determine the threshold concentration of toxic substances for aquatic plants.
10.4
Organics
70.4.7
Hydrocarbons
Law et al. [688] have described procedures for the determination of hydrocarbons
(especially petroleum hydrocarbon residues from oil spills) in marine biota and
related environmental samples. Basic procedures for sample collection, extraction,
and cleanup are outlined, together with the methodology for fluorescence analysis.
70.4.2
Chlorinated Insecticides
Sackmauereva et al. [677, 678] have described the method, given below, for the
determination of chlorinated insecticides (BHC isomers, DDE, DDT, and hexachlorobenzene) in water weeds. In this method, a weighed portion of sample is dried at room
temperature and homogenized. From the pulverized sample, 20 g are taken and
extracted with petroleum ether in a Soxhlet apparatus for 12 h. The concentrated
extract is purified from coextracts on a Florisil filled column activated by heating at
120°C for 48 h with addition of 5 % water to the cooled column. Insecticides are
eluted from the column with 15 % dichloromethane in petroleum ether. The eluate is
concentrated to a volume of 1 ml and analysed by gas chromatography [679-683].
The following chlorinated insecticides can be determined in amounts down to the
concentrations stipulated below.
a-BHC
[}-BHC
y-BHC
&-BHC
p,p'-DDE
o,p'-DDT
p,p'-DDD
p,p'-DDT
0.15 mg kg- 1
0.75 mg kg- 1
0.2 mg kg- 1
0.15 mg kg- 1
0.45 mg kg- 1
0.5 mg kg- 1
1.5 mg kg- 1
1.5 mg kg- 1
Sackmauereva et al. [677] used thin layer chromatography on silica plates to confirm
the identity of chlorinated insecticides previously identified by gas chromatography.
The compounds can be separated by single or repeated one-dimensional development
in n-heptane or in n-heptane containing 0.3 % ethanol. The plate is dried at 65 °c for
10 min and detected by spraying with a solution of silver nitrate plus 2 phenoxyethanol [684, 685]. Thereafter the plate was dried at 65 °c for 10 min and illuminated with
an ultraviolet light (A = 254 nm) until spots representing the smallest amounts of
standards were visible (10-15 min).
Using the gas chromatography methods, Sackmauereva [677] obtained from spiked
samples the four BHC isomers at 93-103.5 % recovery. Both DDT and DDE were