172 Organic compounds in soils, sediments & sludges
been employed to better investigate the real influence of the microwave-assisted extractions on the final results. These workers discuss advantages of such methodology in
comparison with other established microwave units for the routine speciation analysis
or organomercury and organotin compounds. These advantages include a capability
of using disposable glass vials, a self-tuning mode to provide an accurate control of the
temperature and pressure inside of the vials, and the possibility of performing automated sequence of extractions with low sample size. The results obtained in this work
demonstrated that such technology provides a fast and reliable quantitative extraction
of the organometallic species in a wide range of extraction conditions even when the
multi-elemental (Sn and Hg) species-specific determination is carried out.
7.1 ORGANOARSENIC COMPOUNDS
Maher et al [2] has described a method for the determination of down to 0l01 mg kg
−1
of organoarsenic compounds in marine sediments. In this procedure the organoarsenic
compounds are separated from an extract of the sediment by ion exchange chromatography, the isolated organoarsenic compounds are reduced to arsines with sodium
borohydride and collected in a cold trap. Controlled evaporation of the arsine fractions
and detection by atomic absorption spectrometry complete the analysis.
Odanaka et al [3] have reported the application of gas chromatography with
multiple ion detection after hydride generation with sodium borohydride to the
determination of mono and dimethyl arsenic compounds, trimethylarsenic oxide
and inorganic arsenic in soil and sediment; Recoveries in spiking experiments were
100–102% (mono and dimethylarsenic compounds and inorganic arsenic) and 72%
(trimethyl arsenic oxide).
7.2 ORGANOLEAD COMPOUNDS
Potter et al [4] acetified a petroleum ether extract of the sediment with dilute nitric
acid to pH 5–6. This aqueous extract was neutralised with aqueous sodium hydroxide
prior to the analysis by gas chromatography.
Potter et al [4] showed that recovery of alkyllead salts obtained from sediments
was 90% for Et 3 PbC1, 75% for Et 2 PbC1 2 , and 40% for Me 2 PbC1 2 . Extraction of
Et 2 PbC1 2 added to sediment, containing no alkylleads, from a clean and polluted
river, from a clean and polluted canal, and from road drainage grids gave recoveries
of between 65 and 75%. The lowest detectable concentration of alkyllead salts was
2 mg kg
−1 dry weight of sediment. Extraction of the lowest detectable concentration
of tetraalkyllead was 0.02 mg kg
−1 dry weight of sediment. By extracting samples of
filtered water with one-tenth their volume of petroleum either, tetraalkyllead could be
detected down to concentrations of 0.002 mgL
−1 in water.
Using these procedures Potter et al [4] found up to 100 mg kg
−1 of tetraalkyllead
in some samples of drainage grid sediment. No alkyllead compounds were detected in
the filtered water from any of these sediment samples.
Chau et al in a series of papers issued between 1979 and 1984 discussed various
methods for the determination of alkyllead compounds in sediments [5–8].
been employed to better investigate the real influence of the microwave-assisted extractions on the final results. These workers discuss advantages of such methodology in
comparison with other established microwave units for the routine speciation analysis
or organomercury and organotin compounds. These advantages include a capability
of using disposable glass vials, a self-tuning mode to provide an accurate control of the
temperature and pressure inside of the vials, and the possibility of performing automated sequence of extractions with low sample size. The results obtained in this work
demonstrated that such technology provides a fast and reliable quantitative extraction
of the organometallic species in a wide range of extraction conditions even when the
multi-elemental (Sn and Hg) species-specific determination is carried out.
7.1 ORGANOARSENIC COMPOUNDS
Maher et al [2] has described a method for the determination of down to 0l01 mg kg
−1
of organoarsenic compounds in marine sediments. In this procedure the organoarsenic
compounds are separated from an extract of the sediment by ion exchange chromatography, the isolated organoarsenic compounds are reduced to arsines with sodium
borohydride and collected in a cold trap. Controlled evaporation of the arsine fractions
and detection by atomic absorption spectrometry complete the analysis.
Odanaka et al [3] have reported the application of gas chromatography with
multiple ion detection after hydride generation with sodium borohydride to the
determination of mono and dimethyl arsenic compounds, trimethylarsenic oxide
and inorganic arsenic in soil and sediment; Recoveries in spiking experiments were
100–102% (mono and dimethylarsenic compounds and inorganic arsenic) and 72%
(trimethyl arsenic oxide).
7.2 ORGANOLEAD COMPOUNDS
Potter et al [4] acetified a petroleum ether extract of the sediment with dilute nitric
acid to pH 5–6. This aqueous extract was neutralised with aqueous sodium hydroxide
prior to the analysis by gas chromatography.
Potter et al [4] showed that recovery of alkyllead salts obtained from sediments
was 90% for Et 3 PbC1, 75% for Et 2 PbC1 2 , and 40% for Me 2 PbC1 2 . Extraction of
Et 2 PbC1 2 added to sediment, containing no alkylleads, from a clean and polluted
river, from a clean and polluted canal, and from road drainage grids gave recoveries
of between 65 and 75%. The lowest detectable concentration of alkyllead salts was
2 mg kg
−1 dry weight of sediment. Extraction of the lowest detectable concentration
of tetraalkyllead was 0.02 mg kg
−1 dry weight of sediment. By extracting samples of
filtered water with one-tenth their volume of petroleum either, tetraalkyllead could be
detected down to concentrations of 0.002 mgL
−1 in water.
Using these procedures Potter et al [4] found up to 100 mg kg
−1 of tetraalkyllead
in some samples of drainage grid sediment. No alkyllead compounds were detected in
the filtered water from any of these sediment samples.
Chau et al in a series of papers issued between 1979 and 1984 discussed various
methods for the determination of alkyllead compounds in sediments [5–8].