Organometallic compounds in saline sediments 209
Atomic absorption spectrometry
Andreae and Byrd et al [15] have pointed out that methystannanes produced by hydridisation of methyltin compounds are both stable and volatile with boiling points ranging
from 0
◦ C to 59
◦ C.
Hodge et al [16] determined nanogram quantities of the halides of methyltin,
dimethyltin, trimethyltin, diethyltin, triethyltin, n-butyltin, di-n-butyltin, tri-nbutyltin, phenyltin and inorganic tin (IV) in marine sediments by a procedure involving
reaction with sodium borohydride to convert to tin hydrides, which are then detected
by atomic absorption spectrometry. The compounds are separated on the basis of their
differing boiling points, which range from 1.4
◦ C (CH 3 SnH 3 ) to 280
◦ C (n-C 4 H 4 ) 3 SnH).
Detection limits range from 0.4 µg kg
−1 -(SnIV) to 2 µg kg
−1 (tri-n-butyltinchloride).
Stannane and the organotin hydrides evolve from the hydride trap in such a manner
that they can be identified by a ‘retention time’. Tin levels in core samples taken in
Narragonsett Bay, USA (expressed as total tin) ranged from 1 mg kg
−1 (pre 1900) to
20 mg kg
−1 in present day samples.
To determine methyltin, butyltin and inorganic tin in Great Bay estuary sediments, Randall et al [17] extracted the freeze dried sediment with 2.5 mol l
−1
calcium chloride and 2.5 mol l
−1 hydrochloric acid and analysed by hydride generation atomic absorption spectrometry. Detection limits for inorganic tin and tributyltin
were 2.2 ng kg
−1 and 0.6 ng kg
−1 respectively. Recoveries of methyltin and butyltin
species from spiking experiments were greater than 70 ± 10%. Tributyltin was
found in all sampled sites, probably originating from tributyltin based antifouling
paints.
Chromatographic methods have been applied with hydridization. Jackson et al
[18] used a commercial purge and trap apparatus fitted to a packed gas chromatographic column and flame photometric detector to achieve a 0.1 ng detection. Purge
and trap procedures followed by boiling point separations and detection by spectrophotometric methods yield detection limits in water of between 0.01 and 1 ng. Detection
of SnH emission by flame emission gives the greatest sensitivity.
Sinex et al [19] determined methyltin compounds in amounts down to 3–5 pg (as
Sn absolute), i.e. the sub-µg kg
−1 level, in marine sediments by a procedure involving
reaction with sodium borohydride to produce tin hydrides, followed by purge and trap
analysis then gas chromatography with mass spectrometric detection.
High performance liquid chromatography
Chiron et al [20] determined butyl and phenyltin compounds in sediments by
pressurised liquid chromatography coupled with individually coupled plasma mass
spectrometry. Roasenberg et al [21] similarly used high performance liquid chromatography coupled with APCI mass spectrometry to determine organotin compounds in
saline sediments.
Detection limits
As shown in Table 9.2 detection limits available are well within the requirements to
be met when considering environmental sediments.
Atomic absorption spectrometry
Andreae and Byrd et al [15] have pointed out that methystannanes produced by hydridisation of methyltin compounds are both stable and volatile with boiling points ranging
from 0
◦ C to 59
◦ C.
Hodge et al [16] determined nanogram quantities of the halides of methyltin,
dimethyltin, trimethyltin, diethyltin, triethyltin, n-butyltin, di-n-butyltin, tri-nbutyltin, phenyltin and inorganic tin (IV) in marine sediments by a procedure involving
reaction with sodium borohydride to convert to tin hydrides, which are then detected
by atomic absorption spectrometry. The compounds are separated on the basis of their
differing boiling points, which range from 1.4
◦ C (CH 3 SnH 3 ) to 280
◦ C (n-C 4 H 4 ) 3 SnH).
Detection limits range from 0.4 µg kg
−1 -(SnIV) to 2 µg kg
−1 (tri-n-butyltinchloride).
Stannane and the organotin hydrides evolve from the hydride trap in such a manner
that they can be identified by a ‘retention time’. Tin levels in core samples taken in
Narragonsett Bay, USA (expressed as total tin) ranged from 1 mg kg
−1 (pre 1900) to
20 mg kg
−1 in present day samples.
To determine methyltin, butyltin and inorganic tin in Great Bay estuary sediments, Randall et al [17] extracted the freeze dried sediment with 2.5 mol l
−1
calcium chloride and 2.5 mol l
−1 hydrochloric acid and analysed by hydride generation atomic absorption spectrometry. Detection limits for inorganic tin and tributyltin
were 2.2 ng kg
−1 and 0.6 ng kg
−1 respectively. Recoveries of methyltin and butyltin
species from spiking experiments were greater than 70 ± 10%. Tributyltin was
found in all sampled sites, probably originating from tributyltin based antifouling
paints.
Chromatographic methods have been applied with hydridization. Jackson et al
[18] used a commercial purge and trap apparatus fitted to a packed gas chromatographic column and flame photometric detector to achieve a 0.1 ng detection. Purge
and trap procedures followed by boiling point separations and detection by spectrophotometric methods yield detection limits in water of between 0.01 and 1 ng. Detection
of SnH emission by flame emission gives the greatest sensitivity.
Sinex et al [19] determined methyltin compounds in amounts down to 3–5 pg (as
Sn absolute), i.e. the sub-µg kg
−1 level, in marine sediments by a procedure involving
reaction with sodium borohydride to produce tin hydrides, followed by purge and trap
analysis then gas chromatography with mass spectrometric detection.
High performance liquid chromatography
Chiron et al [20] determined butyl and phenyltin compounds in sediments by
pressurised liquid chromatography coupled with individually coupled plasma mass
spectrometry. Roasenberg et al [21] similarly used high performance liquid chromatography coupled with APCI mass spectrometry to determine organotin compounds in
saline sediments.
Detection limits
As shown in Table 9.2 detection limits available are well within the requirements to
be met when considering environmental sediments.