Chapter 5
Extraction of organic compounds
from sediments
5.1 NON-SALINE SEDIMENTS
Various procedures have been used to isolate organic compounds from non-saline sediments, preparatory to analysis. The simplest methods is direct solvent extraction.
Various solvents have been used – n-hexane extracts hydrocarbons, chlorophenols
and chlorinated insecticides from sediments prior to analysis by gas chromatography.
Benzene also extracts hydrocarbons from sediments. Methanol and acetone extract
chlorophylls from algae prior to spectroscopy, thin-layer chromatography or high performance liquid chromatography – methylene dichloride extracts alkyl phosphates,
organophosphorus insecticides and herbicides from sediments, and to separate polyaromatic hydrocarbons from fish prior to gas chromatography. Petroleum ether
and hexane-acetone are useful for the extraction of non-volatile chloro compounds,
chlorinated insecticides and polychlorinated byphenyls from sediments and crustacea.
Acetonitrile or acetonitrile followed by methylene dichloride and petroleum ether are
useful solvents for isolating miscellaneous unknown organic compounds from fish
and sediments, prior to examination by gas chromatography and mass spectrometry
to achieve definitive identification.
Lopez-Avila et al [1] investigated the efficiency of dichloromethane extraction
procedures for the isolation of organic compounds from sediments prior to gas
chromatography-mass spectrometry. The compounds investigated were the 51 priority
pollutants listed by the Environmental Protection Agency, USA.
Harrison and Young et al [2] present results of tests to determine the efficiency
of, and factors affecting, the extraction of semi-volatile organic priority pollutants
from solid samples, using modified Soxhlet procedures. There were marked differences
in the efficiency of extraction for different pollutants. The most important factor in
obtaining maximal recovery appeared to be the contact period during extraction, but
extraction periods longer than 24 hours resulted in significant errors due to solvent
losses.
Nowicki et al [3] point out that in the development of a Soxhlet sample preparation
technique for sediment samples, the empty paper Soxhlet thimbles contained organic
contaminants which adversely affected results. Glass thimbles tried and found to the
satisfactory. The authors detail the identification of organics solvent-extracted from
Extraction of organic compounds
from sediments
5.1 NON-SALINE SEDIMENTS
Various procedures have been used to isolate organic compounds from non-saline sediments, preparatory to analysis. The simplest methods is direct solvent extraction.
Various solvents have been used – n-hexane extracts hydrocarbons, chlorophenols
and chlorinated insecticides from sediments prior to analysis by gas chromatography.
Benzene also extracts hydrocarbons from sediments. Methanol and acetone extract
chlorophylls from algae prior to spectroscopy, thin-layer chromatography or high performance liquid chromatography – methylene dichloride extracts alkyl phosphates,
organophosphorus insecticides and herbicides from sediments, and to separate polyaromatic hydrocarbons from fish prior to gas chromatography. Petroleum ether
and hexane-acetone are useful for the extraction of non-volatile chloro compounds,
chlorinated insecticides and polychlorinated byphenyls from sediments and crustacea.
Acetonitrile or acetonitrile followed by methylene dichloride and petroleum ether are
useful solvents for isolating miscellaneous unknown organic compounds from fish
and sediments, prior to examination by gas chromatography and mass spectrometry
to achieve definitive identification.
Lopez-Avila et al [1] investigated the efficiency of dichloromethane extraction
procedures for the isolation of organic compounds from sediments prior to gas
chromatography-mass spectrometry. The compounds investigated were the 51 priority
pollutants listed by the Environmental Protection Agency, USA.
Harrison and Young et al [2] present results of tests to determine the efficiency
of, and factors affecting, the extraction of semi-volatile organic priority pollutants
from solid samples, using modified Soxhlet procedures. There were marked differences
in the efficiency of extraction for different pollutants. The most important factor in
obtaining maximal recovery appeared to be the contact period during extraction, but
extraction periods longer than 24 hours resulted in significant errors due to solvent
losses.
Nowicki et al [3] point out that in the development of a Soxhlet sample preparation
technique for sediment samples, the empty paper Soxhlet thimbles contained organic
contaminants which adversely affected results. Glass thimbles tried and found to the
satisfactory. The authors detail the identification of organics solvent-extracted from