Chapter 7
Organometallic compounds
in non-saline sediments
Some elements such as arsenic, antimony, bismuth, selenium, mercury, lead and tin
can exist in solid matter in both inorganic and organic forms. The organic forms
of the element may originate either by direct contamination of the solid by organic
compounds of industrial origin or by naturally occurring biomethylation processes
whereby inorganic forms of metals such as mercury and selenium are converted to the
organic form, for example, in fish tissues or in sediments. Suitable handling procedures
both during sampling and during analysis are necessary to avoid losses of metals in
such instances.
Several sample digestion techniques, some involving a subsequent extraction with
an organic solvent, have been described for the determination of organometallic
compounds in sediments.
Successive extractions of the solid with 6 N hydrochloric acid and sodium hydroxide have been used to extract, respectively, total and organic arsenic from plankton
and sediments prior to analysis by spectroscopic or hydride generation atomic
absorption spectrometric techniques. Aqueous sulphuric acid decomposition has also
been used in the case of organoarsenic compounds in fish and sulphuric-perchloric
acids or sulphuric-perchloric acids-hydrogen peroxide have been used in the case
of organomercury compounds prior to analysis, respectively, by neutron activation
analysis or atomic absorption spectrometry. Nitric-perchloric-hydrofluoric acid mixtures have been used to decompose organotin compounds in sediments prior to their
determination by hydride generation atomic absorption spectrometry.
Organomercury compounds have been digested with sodium hydroxide prior to
extraction with toluene and determination by cold vapour atomic absorption spectrometry, gas chromatography or high performance liquid chromatography. Direct solvent
extraction with benzene, toluene or chloroform separates organolead and organomercury compounds from sediments prior to analysis by gas chromatography or column
chromatography.
Combinations of digestion reagents and sediment extraction have also been
used. Thus, nitric acid digestion followed by hexane extraction separates organotin
compounds from fish. Methanolic hydrochloric acid or ethereal tropalone separate
organotin compounds from sediments prior to gas chromatographic analysis.
Pencheov-Argona et al [1] have evaluated self-tuning single-mode microwave technology to perform the quantitative routine extraction of organometallic species from
solid matrices of environmental interest. Species-specific isotope dilution analysis has
Organometallic compounds
in non-saline sediments
Some elements such as arsenic, antimony, bismuth, selenium, mercury, lead and tin
can exist in solid matter in both inorganic and organic forms. The organic forms
of the element may originate either by direct contamination of the solid by organic
compounds of industrial origin or by naturally occurring biomethylation processes
whereby inorganic forms of metals such as mercury and selenium are converted to the
organic form, for example, in fish tissues or in sediments. Suitable handling procedures
both during sampling and during analysis are necessary to avoid losses of metals in
such instances.
Several sample digestion techniques, some involving a subsequent extraction with
an organic solvent, have been described for the determination of organometallic
compounds in sediments.
Successive extractions of the solid with 6 N hydrochloric acid and sodium hydroxide have been used to extract, respectively, total and organic arsenic from plankton
and sediments prior to analysis by spectroscopic or hydride generation atomic
absorption spectrometric techniques. Aqueous sulphuric acid decomposition has also
been used in the case of organoarsenic compounds in fish and sulphuric-perchloric
acids or sulphuric-perchloric acids-hydrogen peroxide have been used in the case
of organomercury compounds prior to analysis, respectively, by neutron activation
analysis or atomic absorption spectrometry. Nitric-perchloric-hydrofluoric acid mixtures have been used to decompose organotin compounds in sediments prior to their
determination by hydride generation atomic absorption spectrometry.
Organomercury compounds have been digested with sodium hydroxide prior to
extraction with toluene and determination by cold vapour atomic absorption spectrometry, gas chromatography or high performance liquid chromatography. Direct solvent
extraction with benzene, toluene or chloroform separates organolead and organomercury compounds from sediments prior to analysis by gas chromatography or column
chromatography.
Combinations of digestion reagents and sediment extraction have also been
used. Thus, nitric acid digestion followed by hexane extraction separates organotin
compounds from fish. Methanolic hydrochloric acid or ethereal tropalone separate
organotin compounds from sediments prior to gas chromatographic analysis.
Pencheov-Argona et al [1] have evaluated self-tuning single-mode microwave technology to perform the quantitative routine extraction of organometallic species from
solid matrices of environmental interest. Species-specific isotope dilution analysis has