Simultaneous Determination of Arsenic, Antimony and Selenium in Aqueous Matrices by Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry

Abstract

A method for the simultaneous determination of As, Se and Sb in aqueous matrices by ETV–ICP-MS has been developed. Complex interactions between the analytes and various chemical modifiers are described. A mixed modifier of Pd(NO ₃ ) ₂ –Ni(NO ₃ ) ₂ was finally selected for quantitative multi-element analysis. Criteria of merit of the proposed method include a 0–100 ng g ^-1 linear range for As and Sb and 0.5–100 ng g ^-1 for Se. Internal standardisation using Te was used to help produce repeatability of 3.9% for As, 6.9% for Se and 2.1% for Sb at the 1 ng g ^-1 level. Detection limits of 0.03, 0.08 and 0.01 ng g ^-1 for As, Se and Sb, respectively, are routinely achievable. The accuracy of the proposed method was demonstrated with the analysis of several reference waters. A severe negative interference on Se by high HCl concentrations could be overcome with the use of a Pd(NO ₃ ) ₂ –Mg(NO ₃ ) ₂ –ascorbic acid chemical modifier.