40 Organic compounds in soils, sediments & sludges
gas to the ATR/IR flow cell. To increase the trapping efficiency, the ATR crystal was
coated with a hydrophobic polyisobutylene polymer that acted as the SPME phase. The
method proved to be very sensitive in the detection of semivolatile compounds in soils.
The relationship between various parameters affecting chemical quantitation, such as
the film thickness, gas flow rate and water contents, was also studied. Three difference
compounds, 1-chloronaphthalene, nitrobenzene, and 2-chloro-Toluene, were used to
investigate the feasibility of this method in the analysis of organic compounds in sand
and soil. Results indicated a linear relationship between concentration and IR signals
can be obtained for the three analytes. The detection limit of this method was in the
range of 200–300 ppb.
Earlier reviews on this subject, are, in view of recent findings, irrelevant [21, 226].
Mass spectrometry
Bianchi et al [227] and Yokouchi and Sano et al [248] obtained good recoveries
of volatile organic compounds in soils employing thermal vaporisation followed by
trapping on Tenax GC and analysis by gas chromatography-mass spectrometry.
Krock and Wilkins et al [229] used multidimensional gas chromatography with
infrared and mass spectrometric detection to determine organic compounds in soil.
Barrio et al [230] used pyrolysis-gas chromatography to study organic matter evolution in sewage sludge-amended soils. Nitrogen-phosphorus specific flame ionisation
and mass spectrometric detectors were used.
Other workers [231–233] have discussed gas chromatography-mass spectrometry.
Kostianinen et al [234] have described a new method, purge and membrane mass spectrometry, for the analysis of volatile organic compounds in water and soil samples. In
this method, volatile organic compounds are purged from water or soil samples with
an inert gas and the stream is directed through a sheet membrane module. The volatile
organic compounds pervaporate through the membrane directly into the ion source of
a mass spectrometer. The limits of detection for nonpolar volatile organic compounds
such as halogenated hydrocarbons, benzene, toluene and xylenes were at low microgem per kilogram levels in soil samples. The correlation coefficient measured for the
compounds studied were typically better than 0.9999 and 0.9975 in water and soil
samples, respectively. The relative standard deviations were between 0.5 and 20.% for
water samples and between 4.8 and 14.0% for soil samples. These results demonstrate
excellent linearity and repeatability. Purge and membrane mass spectrometry thus provides a highly sensitive, selective, accurate, solvent-free and rapid analytical method.
Tens of samples can be analysed within an hour.
Various other workers have reported on the determination of volatile organic compounds in soils, [235] and landfill soils [223]. Soil fumigants such as methyl bromide
have also been determined by this technique [236]. Trifluoroacetic acid is a breakdown
product of hydrofluorocarbons and hydrochlorofluorocarbon refrigerant products in
the atmosphere and, as such, due to the known toxicity of trifluoroacetic acid, it is
important to be able to determine it in the atmosphere, water and soil from an environmental point of view [237]. In this method the trifluoroacetic acid is extracted from the
soil sample by sulphuric acid and methanol, which is then followed by the derivatised
to the methyl ester. The highly volatile methyl ester is then analysed with a recovery of
gas to the ATR/IR flow cell. To increase the trapping efficiency, the ATR crystal was
coated with a hydrophobic polyisobutylene polymer that acted as the SPME phase. The
method proved to be very sensitive in the detection of semivolatile compounds in soils.
The relationship between various parameters affecting chemical quantitation, such as
the film thickness, gas flow rate and water contents, was also studied. Three difference
compounds, 1-chloronaphthalene, nitrobenzene, and 2-chloro-Toluene, were used to
investigate the feasibility of this method in the analysis of organic compounds in sand
and soil. Results indicated a linear relationship between concentration and IR signals
can be obtained for the three analytes. The detection limit of this method was in the
range of 200–300 ppb.
Earlier reviews on this subject, are, in view of recent findings, irrelevant [21, 226].
Mass spectrometry
Bianchi et al [227] and Yokouchi and Sano et al [248] obtained good recoveries
of volatile organic compounds in soils employing thermal vaporisation followed by
trapping on Tenax GC and analysis by gas chromatography-mass spectrometry.
Krock and Wilkins et al [229] used multidimensional gas chromatography with
infrared and mass spectrometric detection to determine organic compounds in soil.
Barrio et al [230] used pyrolysis-gas chromatography to study organic matter evolution in sewage sludge-amended soils. Nitrogen-phosphorus specific flame ionisation
and mass spectrometric detectors were used.
Other workers [231–233] have discussed gas chromatography-mass spectrometry.
Kostianinen et al [234] have described a new method, purge and membrane mass spectrometry, for the analysis of volatile organic compounds in water and soil samples. In
this method, volatile organic compounds are purged from water or soil samples with
an inert gas and the stream is directed through a sheet membrane module. The volatile
organic compounds pervaporate through the membrane directly into the ion source of
a mass spectrometer. The limits of detection for nonpolar volatile organic compounds
such as halogenated hydrocarbons, benzene, toluene and xylenes were at low microgem per kilogram levels in soil samples. The correlation coefficient measured for the
compounds studied were typically better than 0.9999 and 0.9975 in water and soil
samples, respectively. The relative standard deviations were between 0.5 and 20.% for
water samples and between 4.8 and 14.0% for soil samples. These results demonstrate
excellent linearity and repeatability. Purge and membrane mass spectrometry thus provides a highly sensitive, selective, accurate, solvent-free and rapid analytical method.
Tens of samples can be analysed within an hour.
Various other workers have reported on the determination of volatile organic compounds in soils, [235] and landfill soils [223]. Soil fumigants such as methyl bromide
have also been determined by this technique [236]. Trifluoroacetic acid is a breakdown
product of hydrofluorocarbons and hydrochlorofluorocarbon refrigerant products in
the atmosphere and, as such, due to the known toxicity of trifluoroacetic acid, it is
important to be able to determine it in the atmosphere, water and soil from an environmental point of view [237]. In this method the trifluoroacetic acid is extracted from the
soil sample by sulphuric acid and methanol, which is then followed by the derivatised
to the methyl ester. The highly volatile methyl ester is then analysed with a recovery of