Simultaneous determination of arsenic and selenium species in phosphoric acid extracts of sediment samples by HPLC-ICP-MS

• Published in: Analytica chimica acta 2004-11, Vol.527 (1), p.97-104
• Main Authors: Orero Iserte, L., Roig-Navarro, A.F., Hernández, F.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Arsenic; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; HPLC; ICP-MS; Other chromatographic methods; Sediment; Selenium; Speciation; Spectrometric and optical methods
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2004.08.001

A new method for the multielemental determination of arsenic and selenium species in sediment extracts is detailed. Anion exchange separation of As(III), As(V), DMA, MMA, Se(IV) and Se(VI) coupled to ICP-MS detection was accomplished in 10 min on a Hamilton PRP-X100 column with step gradient of a NH 4H 2PO 4 based mobile phase (pH = 6). The extraction procedure used 1 g of dry sediment and 12.5 mL of phosphoric acid. One hour of extraction time (end-over-end shaking) and an acid concentration of 0.3 M were regarded as optimum. The estimated detection limits in the sediment ranged between 2 and 40 ng g −1 for the species analysed. Precision, determined at two levels of concentration showed values of coefficient of variation below 20% for the low level (near the LOD) and below 10% for the high level (10 times the low level). Accuracy of the method was assessed through calculation of the recovery of the spiked sediment. Recoveries ranged between 80 and 120% for all the species analysed with the exception of As(III). This low recovery was thoroughly studied and explained through a conversion process of As(III) into As(V) by an air-oxygen oxidation mechanism during the drying step. The method was regarded as suitable for the proper assessment of the potential toxicity of the sediment.