Method validation for arsenic speciation in contaminated soil by HPLC-ICP-MS coupling method

Abstract

In this work, we have highlighted the importance of the HPLC-ICP-MS for speciation of inorganic and organic species in trace amounts. The study employs a chromatographic separation prior to analysis of arsenic species by ICP-MS as a detection technique. The chromatographic conditions are selected to achieve excellent separation of the four main arsenic species. Several validation parameters such as linearity, detection limit, quantification limit, precision, accuracy and recovery were studied under optimized HPLC-ICP-MS conditions.The limits of quantification for AsIII, dimethylarsinic acid DMA, Monomethylarsonic acid (MMA) and AsV in soils were 0.047, 0.082, 0.168 and 0.167 μg g−1 respectively. The recovery tests and analysis of certified reference material demonstrate the excellent performance, accuracy and precision of HPLC-ICP-MS method. The satisfactory results of speciation by HPLC-ICP-MS showed that the majority form of arsenic in soil extracts is arsenate, but there are also arsenite and traces of DMA. Arsenic-species in the five soil samples ranged from 17.9 to 67.52 μg g−1. A good correlation was obtained from the comparison study between the sum of the arsenic species concentration and the total Arsenic (tAs).