Sequential separation, ICP – MS trace determination of As (III), Sb (III), and Bi (III) in the alloys, water, environmental and human samples

Abstract

ABSTRACT New approach for liquid-liquid extraction, speciation, sequential separation, and ICP – MS trace detection of As, Sb, and Bi utilising synthetic p-carboxycalix[6]benzo crown hydroxamic acid (PCCBCHA) is described. As, Sb, and Bi are extracted into dichloromethane at pH 5.5, 1.5 and 2.0 M HCl, respectively, and determined in nanogram by ICP – MS in the presence of cations and anions. The distribution constant varies with changes in PCCBCHA concentration, pH/molarity of HCl, ionic strength, and temperature. As absorbs at λmax 395 nm with a molar absorptivity 1.15 × 104 L mol−1 cm−1, Sb has λmax 425 nm with a molar absorptivity 1.10 × 104 L mol−1 cm−1 and Bi has λmax 425 nm with molar absorptivity 1.36 × 104 mol−1 L cm−1. The extract followed Beer’s Law for As (III) (0.99–8.916 µg mL−1, RSD 2.4%), Sb (III) (0.99–15.84 µg mL−1, RSD 2.5%), and Bi(III) (1.50–11.76 µg mL−1, RSD 2.6%) and increased. The sensitivity is increased with a factor of 60 folds by injecting the extracts directly into the plasma for ICP – MS measurement with LOD for As 2.0 mg mL−1, Sb 0.5 ng mL−1 and Bi 0.10 ng mL−1. Trivalent and pentavalent forms of As, Sb, and Bi were estimated. This method may be used to determine As, Sb, and Bi in a wide variety of alloys, water, environmental and human samples.