Non-Metals
145
PCBs. After derivatization, the peaks of r-HCH and the saturated DDT metabolites
disappeared.
The saturated DDT metabolites (p,p'-DDT,p,p'-DDD, and o,p-DDT) are converted
quantitatively into the corresponding DDT olefins (p,p'-DDE, p,p'-DDMU, and o,pDDE). The main peak in the ,derivatization' gas chromatogram represents the sum of
p,p'-DDT and p,p'-DDE from the ,basic' chromatogram and is often sufficient for the
Table 7.12
Extraction and cleanup procedures used in the determination of chlorinated insecticides
in fish
Extraction solvent
Sample cleanup
Gas chromatography
Recovery %
Reference
Miscellaneous chlorinated
insecticides
Mix fish with granular soElectron capture p, p'DDE 97.8 423,429
dium sulphate and sand
p, p'DDT 91.2
and Soxhlet extract with
p, p'TDE 94.6
n-hexane
p, p'DDT 89.6
or
dieldrin 89.3
Fish mixed with deactivaElectron capture
ted florisil and extracted
in a column with 1 : 4 v Iv
dichloromethane-hexane
Miscellaneous chlorinated insecticides
Blend fish with sodium sul- Florisil column
95-100
424
phate and solid carbon dioxide. Extract with cyclohexane
Dieldrin
Light petroleum-acetonitrile Florisil column
Flame ionization dieldrin 100
425
partitioning or direct homoand capture degenization with acetonitrile
tection
Photodegradation products Florisil column
Flame ionization
426
of endrin
of silylated or
acetylated derivatives
Dieldrin and polychlorobiphe427
nyls
Gas chromatography-mass
spectrometry
BHC isomers, DOE, DDT
Celite-oleum coElectron capture BHC isomers
428
hexachlorobenzene. Homo- lumn or florisil
93-103
genized fish mixed with
for aldrin- (unstaDDT, DOE 90standard anhydrous sodium hie on celite-o93
sulphate extracted with light leum)
petroleum. Extract concentrated prior to clean-up on
celite-oleum column.