Determination of Arsenic Form in Common Salt by High-Pressure Liquid Chromatography with Inductively Coupled Plasma Mass Spectrometry

Abstract

To clarify the form of arsenic contained in common salt, the application of high-pressure liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICP-MS) was examined. The effects of dilution and sodium chloride concentration of the eluent on the chromatogram were studied. As^Ⅴ and As^Ⅲ both inorganic substances and arsenobetaine, an organic substance, were completely separated, and the amount of each of these substances in common salt was clarified. In 0.2 g/100mL sodium chloride solution, the measurement limitation was 0.5 μg/L. Therefore, the measurement limitation was 0.25 mg/L for common salt. It was found that arsenic was chiefly included as the inorganic substance, As^Ⅴ by analysis using this method for common salts, by which arsenic was detected in our past study. On the other hand, when the arsenic compounds were heated above 200°C, arsenic was confirmed to change into As^Ⅴ. The possible change of arsenic into As^Ⅴ was suggested to occur during heating processes such as drying when arsenic compounds are mixed with the raw material of salt.