Determination of methyltin species in sediments using a pervaporation-gas chromatographic approach

A method for speciation of monomethyltin (MMT), dimethyltin (DMT) and trimethyltin (TMT) in sediments based on the coupling between a pervaporation module, a preconcentration system and a gas chromatograph coupled with a pulsed flame photometric detector is reported. All the species are derivatized using sodium tetraethylborate as an appropriate reagent in order to produce volatile compounds. The experimental approach consists of a high-pressure injection valve. In one of the valve positions, the volatile tin species are driven to an appropriate minicolumn as a sorptive trap placed at the valve loop to preconcentrate the analytes. After a fixed time, the current valve position is changed for the injection mode and desorption of the preconcentrated analytes are obtained by heating in a furnace. Estimated detection limits (of tin) for MMT, DMT and TMT using 500 mg of sample are in all cases lower than 21 ng g(-1). Excellent recoveries (between 90 and 98%) for tin species were obtained by this extremely simple and easily automated setup. Copyright (C) 2002 John Wiley Sons, Ltd.