32 Organic compounds in soils, sediments & sludges
Gas chromatography-mass spectrometry
Teichman et al [155] separated polychlorobiphenyls from chlorinated insecticides in soil samples using gas chromatography coupled with mass spectrometry.
Polychlorobiphenyls were separated from DDT and its analogues and from the
other common chlorinated insecticides by adsorption chromatography on columns
of alumina and charcoal. Elution from alumina columns with increasing fractional
amounts of hexane first isolated Dieldrin and Heptachlor from a mixture of chlorinated insecticides and polychlorobiphenyls. The remaining fractions, when added to
a charcoal column, could be separated into two fractions one containing the chlorinated insecticides, the other containing the polychlorobiphenyls by eluting with
acetone-dimethylethyer (25:75) and benzene, respectively. The polychlorobiphenyls
and insecticides were then determined by gas chromatography on the separate column
eluates without cross reference.
Recovery of polychlorobiphenyls from soil samples obtained in spiking experiments was 100% while that of chlorinated insecticides ranged from 81.5%
(Heptachlor) to 96.3% (Dieldrin). A limit of detection of 6.5 ppb was obtained from
Aroclors 1254 and 1260.
Lopshire et al [156] explored the exchange reaction of chlorine by oxygen with
polychlorobiphenyl anions as a method for compound-selective polychlorobiphenyl
congener detection in a gas chromatography-mass spectrometry-mass spectrometric system. Multiple reaction monitoring allowed separate chromatograms to be
detected for each different polychlorobiphenyl composition from tetra- through
nonachloro. Polychlorobiphenyls were recovered from sediments in another investigation by stema distillation/solvent extraction, followed by enantioselective analysis
using multidimensional electron capture gas chromatography [157].
Alford Stevens et al [158] carried out a multi-laboratory study of automated gas
chromatography-mass spectrometric determinations of polychlorinated biphenyls in
soil. The influence of various factors on the accuracy of analytical results were studied.
Shaker extraction for 12.5 h followed by Florisil chromatography were demonstrated
to be the most reliable methods for extraction and clean-up.
Robbat et al [159] carried out a evaluation of a thermal desorption gas
chromatographic-mass spectrometric method for the on-site detection of polychlorobiphenyls in hexane extracts of soil. Down to 35 mg kg
−1 of polychlorobiphenyl was
detected in soil samples.
Enzyme-based immunoassay
Johnson and Van Emon et al [147] described a quantitative enzyme-based immunoassay procedure for the determination of polychlorinated biphenyls in soils and sediments
and compared the results with those obtained by a gas chromatographic method. The
soil is extracted with methanol or Soxhlet-extracted or extracted with supercritical
fluid. In the case of the latter two extractants, good agreement was obtained between
immunoassay and gas chromatographic methods. Spiking recoveries from soil ranged
from 104% (Aroclor 1248) to 107% (Aroclor 1242). Detection limits were 9 µg/kg
(Aroclor 1245) and 10.5 µg/kg (Aroclor 1242). Chlorinated anisoles, benzenes or
phenols did not interfere.
Gas chromatography-mass spectrometry
Teichman et al [155] separated polychlorobiphenyls from chlorinated insecticides in soil samples using gas chromatography coupled with mass spectrometry.
Polychlorobiphenyls were separated from DDT and its analogues and from the
other common chlorinated insecticides by adsorption chromatography on columns
of alumina and charcoal. Elution from alumina columns with increasing fractional
amounts of hexane first isolated Dieldrin and Heptachlor from a mixture of chlorinated insecticides and polychlorobiphenyls. The remaining fractions, when added to
a charcoal column, could be separated into two fractions one containing the chlorinated insecticides, the other containing the polychlorobiphenyls by eluting with
acetone-dimethylethyer (25:75) and benzene, respectively. The polychlorobiphenyls
and insecticides were then determined by gas chromatography on the separate column
eluates without cross reference.
Recovery of polychlorobiphenyls from soil samples obtained in spiking experiments was 100% while that of chlorinated insecticides ranged from 81.5%
(Heptachlor) to 96.3% (Dieldrin). A limit of detection of 6.5 ppb was obtained from
Aroclors 1254 and 1260.
Lopshire et al [156] explored the exchange reaction of chlorine by oxygen with
polychlorobiphenyl anions as a method for compound-selective polychlorobiphenyl
congener detection in a gas chromatography-mass spectrometry-mass spectrometric system. Multiple reaction monitoring allowed separate chromatograms to be
detected for each different polychlorobiphenyl composition from tetra- through
nonachloro. Polychlorobiphenyls were recovered from sediments in another investigation by stema distillation/solvent extraction, followed by enantioselective analysis
using multidimensional electron capture gas chromatography [157].
Alford Stevens et al [158] carried out a multi-laboratory study of automated gas
chromatography-mass spectrometric determinations of polychlorinated biphenyls in
soil. The influence of various factors on the accuracy of analytical results were studied.
Shaker extraction for 12.5 h followed by Florisil chromatography were demonstrated
to be the most reliable methods for extraction and clean-up.
Robbat et al [159] carried out a evaluation of a thermal desorption gas
chromatographic-mass spectrometric method for the on-site detection of polychlorobiphenyls in hexane extracts of soil. Down to 35 mg kg
−1 of polychlorobiphenyl was
detected in soil samples.
Enzyme-based immunoassay
Johnson and Van Emon et al [147] described a quantitative enzyme-based immunoassay procedure for the determination of polychlorinated biphenyls in soils and sediments
and compared the results with those obtained by a gas chromatographic method. The
soil is extracted with methanol or Soxhlet-extracted or extracted with supercritical
fluid. In the case of the latter two extractants, good agreement was obtained between
immunoassay and gas chromatographic methods. Spiking recoveries from soil ranged
from 104% (Aroclor 1248) to 107% (Aroclor 1242). Detection limits were 9 µg/kg
(Aroclor 1245) and 10.5 µg/kg (Aroclor 1242). Chlorinated anisoles, benzenes or
phenols did not interfere.