Determination of tin in soil by continuous hydride generation and inductively coupled plasma mass spectrometry

A method was investigated for the determination of Sn in soil samples by KOH fusion followed by continuous hydride generation coupled with inductively coupled plasma mass spectrometry (HG-ICP-MS). Sample solutions in 3.0 M HCl were mixed in line with a solution of 2.4% NaBH₄ and 0.25 M KOH to generate stannane gas. The mixture was delivered continuously to a gas/liquid separator and the stannane gas was introduced into a Perkin-Elmer Sciex Elan 6000 ICP-MS for concentration measurements. A method detection limit of 0.45 mg/kg was sufficient for Sn levels commonly found in soil samples. Sn concentrations as low as 2.5 mg/kg were reproducibly measured in soil samples. Sample results by HG-ICP-MS agreed within ±17% relative difference to results by instrumental neutron activation analysis (INAA) and within ±6% relative difference to results by KOH fusion followed by inductively coupled plasma optical emission spectroscopy (ICP-OES).