DETERMINATION OF TRIBUTYLTIN AND DIBUTYLTIN IN SEA-WATER BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ONLINE COUPLED WITH ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

An optimized procedure is described for the separation of tributyltin (TBT) and dibutyltin (DBT) by high performance liquid chromatography ( HPLC) using atomic absorption spectrometry (AAS) as a detection system . An on-line coupling between HPLC and electrothermal atomic absorptio n spectrometry (ETAAS) has been developed; the interface uses a 6-way valve between the outlet of the chromatographic column and the capilla ry of the autosampler arm. With this system 98 mu L of the chromatogra phic stream were injected into the graphite furnace which was preheate d at 120 degrees C; the conditions of its design and working ale descr ibed. With this interface only one fraction of the chromatographic pea k is isolated and its absorbance determined, so the reconstruction of this peak is not needed; this fact makes the procedure quicker and eas ier to carry out. The proposed procedure is applied to the determinati on of TBT and DBT in marine water samples with a previous liquid-liqui d extraction, and the limits of detection (LOD) obtained for TBT and D BT are 31 and 28 ng L(-1), respectively.