Determination of butyltin compounds by high-performance liquid chromatography-hydride generation-electrothermal atomization atomic absorption spectrometry

Abstract

An ultrasensitive method for the determination of butyltin compounds has been developed coupling liquid chromatography with electrothermal atomization atomic absorption spectrometry by means of a hydride generation-in situ trapping system. The eluent coming out from the HPLC column was mixed in a tee piece assembly with hydrochloric acid and sodium tetrahydroborate; the reacting solution was carried through the mixing coil to the gas–liquid separator and the generated hydrides were stripped from the solution, introduced into the graphite atomizer through the quartz tube and collected on a Pd-treated platform. The quartz tube was then removed from the injection hole of the graphite tube and the atomic absorbance measured. For each considered tin species (inorganic tin, monobutyltin, dibutyltin, tributyltin) hydride generation conditions were studied in a multivariate way by a suitable experimental design. The resulting analytical performance of the HG-in situ trapping-ETAAS set-up was adequate for the determination of organotin species in environmental samples and therefore it was used as a metal-specific detector for HPLC analysis of this class of compounds. Detection limits of 0.84, 1.66 and 20.4 ng were obtained for mono-, di- and tributyltin, respectively. The system has been used for the determination of butyltin species in certified reference materials of marine samples such as mussel tissues and sediments.