TIME-BASED DEVICE USED FOR THE DETERMINATION OF TIN BY HYDRIDE GENERATION FLOW-INJECTION ATOMIC-ABSORPTION TECHNIQUES

A time-based device used in conjunction with flow injection hydride generation atomic absorption spectrometry for the determination of tin in biological materials is described. Its configuration was designed for minimal manipulation of the samples with the great advantage of using large volumes of diluted digests. In order to ensure the determination of the analyte directly in the sample digest, several acids were tested for their effect on stannane generation. A mixture of nitric acid and perchloric acid was found to be suitable in an acidity range of 0.5-2.0 mol l(-1); addition of hydrogen peroxide has no effect on the results. Other experimental parameters such as sample and reagent concentrations and volumes, carrier gas flow rate as well as atomizer conditions were optimized by both the simplex and univariate optimization methods. The results were in good agreement. A linear calibration graph was obtained in the range 5-250 mu g l(-1) with a 3 sigma. detection limit of 2.5 mu g l(-1). The relative standard deviations were 4.8 and 2.6% for 5 and 50 mu g l(-1) tin, respectively. The method was applicable with good accuracy to the determination of tin in some biological tissues.