Assessment of acid media effects on the determination of tin by hydride generation-inductively coupled plasma atomic emission spectrometry

The effect of several inorganic (nitric, sulfuric and hydrochloric) and organic (acetic, mercaptoacetic and tartaric) acids on the continuous hydride generation determination of tin by ICP-OES was evaluated. The study was aimed to optimize the efficiency of hydride generation as well as the reduction of interference caused by the presence of concomitant elements. Employing reduction with sodium tetrahydroborate, the highest sensitivity was observed with 2.5 M acetic acid. Effects of signal depression produced by transition and hydride-forming elements were less pronounced with acetic and mercaptoacetic acids. Additionally, sensitivity was found to be less dependent on concentration variations for organic acid media. A significant increase in sensitivity was obtained by hydride generation at temperatures above 20 degreesC. The limit of detection calculated for optimized conditions in acetic acid was 0.1 ng ml(-1). Method repeatability was in the 3.1-4.5% R.S.D. range. The accuracy of this method was tested by analysis of a soil certified reference material (GBW 07405). (C) 2002 Elsevier Science B.V. All rights reserved.