208 Organic compounds in soils, sediments & sludges
high purge efficiencies for mono-, di-, and trimethyltin. Selected ion mode monitoring
with the mass spectrometer gave detection limits for methyltins of 3–5 pg as tin. The
concentration detection limits for a 5 g sediment samples were in the sub-µg kg
−1
level, with a standard deviation of 6–18%, depending upon the methyltin species and
sample type. The method is both selective and specific, eliminating most interference
while permitting positive identification of individual methyltin species. Sample weights
were typically 5 g and these were treated directly with the borate buffered sodium
borohydride reagent.
The recovery of methyltins from sediments was tested by using anoxic, sulfidic clay sediments from a mid-salinity region of Chesapeake Bay. Monomethyltin
(11.2 ng) and dimethyltin (11.5 ng) were completely recovered from sediment.
However, recovery of 10 ng of trimethyltin chloride from sediment was only
about 70%.
Muller et al [12] has described a gas chromatographic method for the determination of tributyltin compounds in sediments. The tributyltin compounds are first
converted to tributylmethyltin by reaction with ethyl magnesium bromide, and then
analysed using capillary gas chromatography with flame photometric detection analyses gas chromatography-mass spectrometry. Tributyltin was found in marine sediments
and could be determined in amounts down to less than 1.0.5 pg L
−1 .
Hattori et al [13] extracted alkyltin compounds from sediments with methanolic
hydrogen chloride and then following mixture with sodium chloride and water, the
mixture was extracted with benzene and converted to hydrides with sodium borohydride and analysed by gas chromatography using an electron capture in amounts down
to 0.02 mg kg
−1 with a recovery of 70–95%.
Labinski et al [14] speciated organotin compounds in sediments by capillary gas
chromatography using helium microwave induced plasma emission spectrometers as
a detector. These workers used the procedure to determine nono, di, tri and some
tetralkytin compounds in sediments. The ionic tin compounds were extracted as
diethyldithio carbamates into pentane then converted to pentyl magnesium bromide
derivatives prior to gas chromatography. Detector limits were 0.05 pg tin equivalent
to 10–30 ng kg
−1 .
Nemanic et al [39] evaluated the efficiency of different extraction procedures for
the simultaneous procedures for the simultaneous determination of butyltin compounds in marine sediments by gas chromatography-mass spectrometry (GC-MS).
Three different polar solvents (acetic acid, a mixture of acetic acid with methanol,
and a mixture of acetic acid, methanol, and water) and three different extraction
approaches (mechanical shaking, ultrasonic, and microwave-assisted extraction) were
used for the extraction of butyltin compounds from PACS-2 certified marine sediment reference material. Before determination by GC-MS, extracted butyltin species
were derivatised with sodium tetraethyl borate and extracted into iso-octane. The
results indicated that 30 minute ultrasonic extraction with 100% acetic provided satisfactory recoveries for all certified butyltins. The developed analytical method was
successfully applied for determination of butyltin compounds in coastal sediments
of the Northern Adriatic Sea. The results demonstrated that butyltins were present
in all sediments analysed over a wide range of concentrations ranging from 3 to
934 ngSn g
−1 (monobutyltin) 3 to 434 ngSn g
−1 (dibutyltin) and 7 to 1215 ng Sn g
−1
(tributyltin).
high purge efficiencies for mono-, di-, and trimethyltin. Selected ion mode monitoring
with the mass spectrometer gave detection limits for methyltins of 3–5 pg as tin. The
concentration detection limits for a 5 g sediment samples were in the sub-µg kg
−1
level, with a standard deviation of 6–18%, depending upon the methyltin species and
sample type. The method is both selective and specific, eliminating most interference
while permitting positive identification of individual methyltin species. Sample weights
were typically 5 g and these were treated directly with the borate buffered sodium
borohydride reagent.
The recovery of methyltins from sediments was tested by using anoxic, sulfidic clay sediments from a mid-salinity region of Chesapeake Bay. Monomethyltin
(11.2 ng) and dimethyltin (11.5 ng) were completely recovered from sediment.
However, recovery of 10 ng of trimethyltin chloride from sediment was only
about 70%.
Muller et al [12] has described a gas chromatographic method for the determination of tributyltin compounds in sediments. The tributyltin compounds are first
converted to tributylmethyltin by reaction with ethyl magnesium bromide, and then
analysed using capillary gas chromatography with flame photometric detection analyses gas chromatography-mass spectrometry. Tributyltin was found in marine sediments
and could be determined in amounts down to less than 1.0.5 pg L
−1 .
Hattori et al [13] extracted alkyltin compounds from sediments with methanolic
hydrogen chloride and then following mixture with sodium chloride and water, the
mixture was extracted with benzene and converted to hydrides with sodium borohydride and analysed by gas chromatography using an electron capture in amounts down
to 0.02 mg kg
−1 with a recovery of 70–95%.
Labinski et al [14] speciated organotin compounds in sediments by capillary gas
chromatography using helium microwave induced plasma emission spectrometers as
a detector. These workers used the procedure to determine nono, di, tri and some
tetralkytin compounds in sediments. The ionic tin compounds were extracted as
diethyldithio carbamates into pentane then converted to pentyl magnesium bromide
derivatives prior to gas chromatography. Detector limits were 0.05 pg tin equivalent
to 10–30 ng kg
−1 .
Nemanic et al [39] evaluated the efficiency of different extraction procedures for
the simultaneous procedures for the simultaneous determination of butyltin compounds in marine sediments by gas chromatography-mass spectrometry (GC-MS).
Three different polar solvents (acetic acid, a mixture of acetic acid with methanol,
and a mixture of acetic acid, methanol, and water) and three different extraction
approaches (mechanical shaking, ultrasonic, and microwave-assisted extraction) were
used for the extraction of butyltin compounds from PACS-2 certified marine sediment reference material. Before determination by GC-MS, extracted butyltin species
were derivatised with sodium tetraethyl borate and extracted into iso-octane. The
results indicated that 30 minute ultrasonic extraction with 100% acetic provided satisfactory recoveries for all certified butyltins. The developed analytical method was
successfully applied for determination of butyltin compounds in coastal sediments
of the Northern Adriatic Sea. The results demonstrated that butyltins were present
in all sediments analysed over a wide range of concentrations ranging from 3 to
934 ngSn g
−1 (monobutyltin) 3 to 434 ngSn g
−1 (dibutyltin) and 7 to 1215 ng Sn g
−1
(tributyltin).