Speciation analysis of butyltin compounds in Chinese seawater by capillary gas chromatography with flame photometric detection using in-situ hydride derivatization followed by headspace solid-phase microextraction

A solvent-free method for the extraction of butyltin compounds from seawater by headspace solid-phase microextraction (SPME) is presented. The butyltin chlorides present in seawater was converted to its hydride forms by sodium tetrahydridoborate prior to extraction. A polydimethylsiloxane (PDMS) coated silica 100 mu m fiber is introduced into the headspace over seawater to extract butyltin hydrides. After extraction, the fiber is directly injected to the injector of gas chromatograph (GC) for desorption, separation and quantification. A laboratory modified flame photometric detector using quartz surface-induced tin emission (QSIL-FPD) was used throughout the experiment. The detection limits obtained with GC-QSIL-FPD for monobutyl, dibutyl, and tributyltin are 19.4, 1.5 and 0.5 ng/l as Sn, respectively. The proposed method was applied to the speciation analysis of butyltin compounds in seawater from different part of the Chinese harbors. (C) 2000 Elsevier Science B.V. All rights reserved.