Headspace solid-phase microextraction of butyltin species in sediments andtheir gas chromatographic determination

A rapid and solvent-free procedure for the simultaneous determination of mo no-, di-, and tributyltin in sediments by headspace solid-phase microextrac tion (SPME) is described. The butyltin chlorides present in sediments were converted into their hydride forms by potassium tetrahydroborate prior to e xtraction. A quartz fiber coated with 100 mum film of polydimethylsiloxane (PDMS) is introduced into the headspace over the matrix to extract butyltin hydrides. After extraction, the fiber is directly inserted into the inject or of the gas chromatograph (GC) for desorption, separation, and quantifica tion. A laboratory modified flame photometric detector using quartz surface -induced tin emission (QSIL-FPD) was used throughout the experiment. The de tection limits obtained with SPME-GC-QSIL-FPD for mono-, di-, and tributylt in are 8.8, 0.16, and 0.05 ng/g as Sn, respectively. The proposed method ha s been validated by analyzing standard reference material CRM-462, and succ essfully used for the determination of butyltin compounds in sediment colle cted from coastal areas of Hong Kong.