Speciation of butyltin compounds in marine sediments with headspace solid phase microextraction and gas chromatography-mass spectrometry

A method for the determination of organotin compounds (monobutyl = MBT, dib utyl = DBT, and tributyltin = TBT) in marine sediments by headspace Solid P hase Microextraction (SPME) has been developed. The analytical procedure in volved 1) extraction of TBT, DBT and MBT from sediments with HCl and methan ol mixture, 2) in situ derivatization with sodium tetraethylborate and 3) h eadspace SPME extraction using a fiber coated with poly(dimethylsiloxane). The derivatized organotin compounds were desorbed into the splitless inject or and simultaneously analyzed by gas chromatography - mass spectrometry. The analytical method was optimized with respect to derivatization reaction and extraction conditions. The detection limits obtained for MET, DBT and TBT ranged from 730 to 969 pg/g as Sn dry weight. Linear calibration curves were obtained for all analytes in the range of 30-1000 ng/L as Sn. Analysi s of a standard reference sediment (CRM 462) demonstrates the suitability o f this method for the determination of butyltin compounds in marine sedimen ts. The application to the determination of TBT, DBT and MBT in a coastal m arine sediment is shown.