Analytical Sciences

Determination of Butyltin Compounds in Aqueous Samples by Gas Chromatography with Flame Photometric Detector and Headspace Solid-Phase Microextraction after in-situ Hydride Derivatization

G. B. JIANG Ž€ÛÂnd J. Y. LIU

Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,P. O. Box 2871, Beijing, 100085, China

A method for the extraction and determination of butyltin species in aqueous samples by solid-phase microextraction(SPME) combined with a capillary gas chromatography-flame photometric detector (GC-FPD) is described. The butyltinspecies was converted to its hydride form by sodium tetrahydroborate (NaBH₄) in a closed headspace vial prior toextraction. A laboratory-assembled SPME device including a fused-silica fiber and a modified microsyringe protectionpart was used throughout the experiment. The extraction was an equilibrium process that depended on the butyltinspecies partitioning between the liquid phase and the fiber. When the equilibrium was reached, the fiber was directlytransferred to a GC column under the protection of a microsyringe, where the analyte was thermally desorbed inside theheated injector and subsequently, separated in a HP-1 capillary column and detected by a laboratory-made flamephotometric detector using quartz surface-induced tin emission. The detection limits based on the signal equal to 3 timesof the base-line noise were 0.2 ug/L, 0.2 ug/L, 0.1 ug/L and 0.02 ug/L for monobutyltin (MBT), dibutyltin (DBT),tributyltin (TBT) and tetrabutyltin (TeBT), respectively. The recovery ranged from 85% to 117%. The proposed methodhas been applied to determination of butyltin species in various aqueous samples.

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