Determination of calcium in natural water samples by atomic absorption spectrometry by adding reduced amounts of lanthanum chloride

Abstract

The concentrations of calcium in river and underground water samples of Kikuchi River and Kikusui-machi in the northern area of Kumamoto Prefecture and in two commercially available drinking water samples, Volvic and Morinomizudayori, were measured by suppressing interference due to coexisting components, such as aluminum, silicate, sulfate and phosphate ions, by adding a smaller amount of lanthanum chloride than that indicated in the JIS method, 2 × 103 ppm. The calcium concentrations measured in the presence of 30 to 50 ppm lanthanum almost agreed with those by chelatemetric titration (EDTA) and inductively coupled plasma atomic emission spectrometry(ICP-AES). The proposed AAS with an acetylene-air flame is a facile and environmentally protective method for the determination of calcium in natural water samples.