Determination of Butyltin and Phenyltin by GC-FPD Following Ethylation by NaBEt4

An organotin speciation method was optimized for the simultaneous determination of mono-, di- and tri-butyltin compounds and mono-, di- and tri-phenyltin compounds in water. The procedure was based on a one-step simultaneous ethylation and extraction using the sodium tetraethylborate reagent directly in the aqueous phase in the presence of an iso-octane layer. Direct extract analysis was performed using capillary gas chromatography and flame photometric detection (GC–FPD). This derivatization procedure reduces drastically the number of analytical steps, thus saving time and improving reliability. Relative detection limits range from 0.4 to 0.8 ng dm−3 for butyltin species and from 0.7 to 2.1 ng dm−3 for phenyltin species; the linearity ranges from 0 to 400 ng dm−3. Analysis of environmental aqueous samples and a Certified Reference Material (CRM) demonstrates the accuracy of the analytical method.