196 Organic compounds in soils, sediments & sludges
determined by a procedure in which the sediments were pre-treated with acetic acid,
mixed with silica and Soxhlet-extracted with benzene/hexane. Humic material and
elemental sulphur were removed by passing the extract through a chromatographic
column containing basic alumina, on which sodium sulphite and sodium hydroxide
were adsorbed. Silica fractionation was followed by gas chromatography to analyse chlorinated pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons.
Recovery experiments with standard solutions gave recoveries of 90–102%.
Japenga et al [36] separated polychlorobiphenyls from chlorinated insecticides by
a procedure involving adsorption chromatography on alumina and charcoal columns,
elution with increasing fractional amounts of hexane on alumina columns, and with
acetone-diethyl ether on charcoal columns. The polychlorinated biphenyls and chlorinated pesticides were then determined by gas chromatography-mass spectrometry on
the separate eluates without interference.
8.1.6.2 Organophosphorus pesticides
Kjolholt et al [37] determined trace amounts of organophosphorus pesticides and
related compounds using capillary gas chromatography and a nitrogen specific
detector.
Acetone-n-hexane extracts of the sediment were partitioned between methylene
chloride and water and subjected to adsorption chromatography and analysed by gas
chromatography recoveries were between 55 and 82% and detection limit in the range
95–220 µg depending on the type of organophosphorus insecticide.
8.1.7 Miscellaneous
8.1.7.1 Priority pollutants
Ozretich and Schroeder et al [38] developed an extraction procedure utilising sonication with acetonitrile and cleanup using Aminopropyl and/or C-18 bonded phase
columns, to prepare marine sediments for priority organic pollutants analysis by gas
chromatography. Recoveries from standard reference and interlaboratory comparison
sediments and tissue preparations compared favourably to published mean values.
Mean recoveries of 22 priority organic pollutants from the sediments ranged from
0% to 84% with a median recovery of 71% and an average percent relative standard
deviation (%RSD) of 9%. The effects of sediment type and storage method on the
spike recoveries are discussed. Some typical results and recoveries obtained by this
procedure are quoted in Table 8.2.
8.1.7.2 Humic and fulvic acids
Hayase et al [39] measured the fluorescence and adsorption spectra of humic acid and
fulvic acid in sediment collected from Tokyo Bay, at 20
◦ C and pH8. The maximal excitation and emission wavelengths for humic acid were longer than those for fulvic acid,
independent of molecular weight, and could therefore be used to differentiate between
humic acid and fulvic acid in marine deposits. Smaller molecules showed greater fluorescence than larger molecules. Fluorescence intensity per weight concentrations unit
increased for humic acid, and decreased for fulvic acid, with increase in adsorption
coefficient.
determined by a procedure in which the sediments were pre-treated with acetic acid,
mixed with silica and Soxhlet-extracted with benzene/hexane. Humic material and
elemental sulphur were removed by passing the extract through a chromatographic
column containing basic alumina, on which sodium sulphite and sodium hydroxide
were adsorbed. Silica fractionation was followed by gas chromatography to analyse chlorinated pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons.
Recovery experiments with standard solutions gave recoveries of 90–102%.
Japenga et al [36] separated polychlorobiphenyls from chlorinated insecticides by
a procedure involving adsorption chromatography on alumina and charcoal columns,
elution with increasing fractional amounts of hexane on alumina columns, and with
acetone-diethyl ether on charcoal columns. The polychlorinated biphenyls and chlorinated pesticides were then determined by gas chromatography-mass spectrometry on
the separate eluates without interference.
8.1.6.2 Organophosphorus pesticides
Kjolholt et al [37] determined trace amounts of organophosphorus pesticides and
related compounds using capillary gas chromatography and a nitrogen specific
detector.
Acetone-n-hexane extracts of the sediment were partitioned between methylene
chloride and water and subjected to adsorption chromatography and analysed by gas
chromatography recoveries were between 55 and 82% and detection limit in the range
95–220 µg depending on the type of organophosphorus insecticide.
8.1.7 Miscellaneous
8.1.7.1 Priority pollutants
Ozretich and Schroeder et al [38] developed an extraction procedure utilising sonication with acetonitrile and cleanup using Aminopropyl and/or C-18 bonded phase
columns, to prepare marine sediments for priority organic pollutants analysis by gas
chromatography. Recoveries from standard reference and interlaboratory comparison
sediments and tissue preparations compared favourably to published mean values.
Mean recoveries of 22 priority organic pollutants from the sediments ranged from
0% to 84% with a median recovery of 71% and an average percent relative standard
deviation (%RSD) of 9%. The effects of sediment type and storage method on the
spike recoveries are discussed. Some typical results and recoveries obtained by this
procedure are quoted in Table 8.2.
8.1.7.2 Humic and fulvic acids
Hayase et al [39] measured the fluorescence and adsorption spectra of humic acid and
fulvic acid in sediment collected from Tokyo Bay, at 20
◦ C and pH8. The maximal excitation and emission wavelengths for humic acid were longer than those for fulvic acid,
independent of molecular weight, and could therefore be used to differentiate between
humic acid and fulvic acid in marine deposits. Smaller molecules showed greater fluorescence than larger molecules. Fluorescence intensity per weight concentrations unit
increased for humic acid, and decreased for fulvic acid, with increase in adsorption
coefficient.