CHAPTER 10 • Occurence, Pathways and Bioaccumulation of Organometallic Compounds
205
standard chromatographic procedures. Liquid chromatography separation techniques
are very powerful, as they generally allow the derivatization stage to be by-passed and
provide a large panel of possible chromatographic procedures, enabling a larger range
of organometallic compounds to be determined. An on-line technique using direct
interfacing between hydride generation methods and combining simultaneously the
preconcentration step by cryofocusing and later chromatography by gentle warming
of the trap can be very easily interfaced with atomic absorption or emission spectrometry. Techniques derived from these procedures achieve the highest sensitivity and ease
of operation in comparison to other methods using off-line preconcentration methods with considerably fewer analytical steps.
In our studies we employed an HPLC-HG-ICP-AES hyphenated method in order
to obtain the determination of mono-, di- and tributyltin species in biotic and abiotic
matrices (Rivaro 1998; Rivaro et al. 1995). Separations were performed on a Partisil
SCX 10 analytical column (10 f!m particle size, 25 cm x 4.6 mm i.d.) (Whatman,
Englewood Cliffs, NJ, USA). The flow rate was 1 ml min- I and no gradient elution devices were used. The mobile phase used was 0.1 M ammonium acetate in 80% methanoll2o% water containing 0.1 % m/v tropolone. The eluent coming out from the HPLC
column was mixed in a PTFE (polytetrafluoroethylene) "T" piece with hydrochloric
acid supplied by a peristaltic pump, with a 0.7 ml min -I flow. The organotin compounds
were converted into their hydrides by addition of NaBH4, supplied by a peristaltic pump
with a 0.7 ml min -I flow in another PTFE "T" piece. Evolved hydrides were drained to
the gas-liquid separator, where an argon flow carried the tin vapours in to the ICPAES torch, while the organic eluent was washed out. The HPLC-ICP determination was
carried out detecting the tin signal every 300 ms with a scanning step of 0 nm, i.e. the
ICP detector was fixed at the analytical tin wavelength Sn(II) 189.989 nm. A schematic
diagram of the HPLC-HG-ICP/AES system is reported in Fig. 10.3.
Figure 10.4 shows the result of a chromatographic separation of a mixture of TBT,
DBT, MBT, and standard solutions.
This analytical method was improved developing a new method for the determination of TBT and DBT by means of LC/MS with particle beam interface (Magi and
Ianni 1998).
10.4
An Example of a "Field Study": The Butyltin Distribution in the
Genoa Oil Port
As an example of the distribution of organotin compounds in the marine environment,
a study carried out in the Genoa oil port is shown. The aim of the present study has
been to follow the seasonal variations of butyltin compounds in water, suspended
particulate matter and mussels, under natural conditions in the Genoa oil port. Mussels are often used as a biomonitor in monitoring programs assessing the quality of
marine environment, because they can provide a time-integrated estimation of the
contaminants in water. A growing number of studies valued the levels of alkyltins in
mussel tissues from a variety of locations worldwide. Nevertheless, the input of
organotins from large vessels in coastal waters has been seldom assessed, because these
vessels spend the majority of the time offshore, where diluition and dispersion processes can reduce the release of TBT in the water.
205
standard chromatographic procedures. Liquid chromatography separation techniques
are very powerful, as they generally allow the derivatization stage to be by-passed and
provide a large panel of possible chromatographic procedures, enabling a larger range
of organometallic compounds to be determined. An on-line technique using direct
interfacing between hydride generation methods and combining simultaneously the
preconcentration step by cryofocusing and later chromatography by gentle warming
of the trap can be very easily interfaced with atomic absorption or emission spectrometry. Techniques derived from these procedures achieve the highest sensitivity and ease
of operation in comparison to other methods using off-line preconcentration methods with considerably fewer analytical steps.
In our studies we employed an HPLC-HG-ICP-AES hyphenated method in order
to obtain the determination of mono-, di- and tributyltin species in biotic and abiotic
matrices (Rivaro 1998; Rivaro et al. 1995). Separations were performed on a Partisil
SCX 10 analytical column (10 f!m particle size, 25 cm x 4.6 mm i.d.) (Whatman,
Englewood Cliffs, NJ, USA). The flow rate was 1 ml min- I and no gradient elution devices were used. The mobile phase used was 0.1 M ammonium acetate in 80% methanoll2o% water containing 0.1 % m/v tropolone. The eluent coming out from the HPLC
column was mixed in a PTFE (polytetrafluoroethylene) "T" piece with hydrochloric
acid supplied by a peristaltic pump, with a 0.7 ml min -I flow. The organotin compounds
were converted into their hydrides by addition of NaBH4, supplied by a peristaltic pump
with a 0.7 ml min -I flow in another PTFE "T" piece. Evolved hydrides were drained to
the gas-liquid separator, where an argon flow carried the tin vapours in to the ICPAES torch, while the organic eluent was washed out. The HPLC-ICP determination was
carried out detecting the tin signal every 300 ms with a scanning step of 0 nm, i.e. the
ICP detector was fixed at the analytical tin wavelength Sn(II) 189.989 nm. A schematic
diagram of the HPLC-HG-ICP/AES system is reported in Fig. 10.3.
Figure 10.4 shows the result of a chromatographic separation of a mixture of TBT,
DBT, MBT, and standard solutions.
This analytical method was improved developing a new method for the determination of TBT and DBT by means of LC/MS with particle beam interface (Magi and
Ianni 1998).
10.4
An Example of a "Field Study": The Butyltin Distribution in the
Genoa Oil Port
As an example of the distribution of organotin compounds in the marine environment,
a study carried out in the Genoa oil port is shown. The aim of the present study has
been to follow the seasonal variations of butyltin compounds in water, suspended
particulate matter and mussels, under natural conditions in the Genoa oil port. Mussels are often used as a biomonitor in monitoring programs assessing the quality of
marine environment, because they can provide a time-integrated estimation of the
contaminants in water. A growing number of studies valued the levels of alkyltins in
mussel tissues from a variety of locations worldwide. Nevertheless, the input of
organotins from large vessels in coastal waters has been seldom assessed, because these
vessels spend the majority of the time offshore, where diluition and dispersion processes can reduce the release of TBT in the water.