IN-SITU DERIVATIZATION AND SUPERCRITICAL-FLUID EXTRACTION FOR THE SIMULTANEOUS DETERMINATION OF BUTYLTIN AND PHENYLTIN COMPOUNDS IN SEDIMENT

A supercritical fluid extraction (SFE) procedure for the simultaneous determination of butyltin and phenyltin compounds in sediment samples was developed. Following a hexyl derivatization onto the sediment with hexylmagnesium bromide, which took place in situ within the extraction cell, SFE was performed in mild thermal conditions (T = 40-degrees-C, P = 350 atm). The recovered SFE extracts were analyzed by gas chromatography with flame photometric detection without any additional cleanup step. This procedure minimizes the sample handling steps, saves analysis time, and reduces the usage of solvent. Analysis of tributyltin in standard reference materials demonstrates the validity of this method. The technique was also successfully applied to the determination of tributyltin, diphenyltin, and triphenyltin in real sediments.