Determination of Butyltin Stabilizers in PVC Using Liquid-Phase Microextraction with Electrothermal Atomic Absorption Spectrometry
M. Kaykhaii* and A. Khatibi
Department of Chemistry, Faculty of Sciences,University of Sistan & Baluchestan, Zahedan 98135-674, Iran
A rapid and highly sensitive method is described for the extraction and determination of di- and tributyltin in PVC samples using headspace liquid phase microextraction followed by an analysis with graphite furnace atomic absorption spectrometry (HS-LPME/GFAAS). The analytes were derivatized in situ with sodium tetraethylborate and concentrated in a 2 µl microdrop of benzyl alcohol suspended from the tip of a conventional GC microsyringe. The ethylated species then were directly transferred into a graphite furnace and quantified. The extractions were carried out for 5 ml sample solution (8 ml vial) adjusted at pH 5, with derivatization at 22 °C for 15 min in a 2% sodium tetraethylborate. The experimental parameters impacting the performance of HS-LPME were also investigated. According to the analysis, the linearity range was from 5.0 to 250.0 ng l-1 with a detection limit of 0.5 ng l-1 for dibutyltin and from 1.7 to 170.0 ng l-1 with a detection limit of 0.17 ng l-1 for tributyltin. Method RSD values were below 1.5%. Finally, the analysis of spiked PVC and water samples revealed that matrix had little effect upon extraction .
Keywords: Organotin compounds (OTC), Headspace liquid phase microextraction (HS-LPME), Poly-vinyl chloride (PVC), Electrothermal atomic absorption spectrometry (Et-AAS)