Application of Cloud-Point Extraction for the Determination of Arsenic using Inductively Coupled Plasma Atomic Emission Spectrometry in Several Pharmaceutical Preparations

Abstract

Application of cloud-point extraction for arsenic determination in pharmaceuticals of various types: Calcium gluconate, solution for injection 100 mg mL-1, Potassium chloride, solution for injection 4 %, and Magnesium sulfate, solution for injection 25 %, was investigated. It has been demonstrated that direct quantitative extraction of arsenic into the micellar phase of Triton X-100 in the form of molybdoarsenic acid is possible only for potassium chloride. Magnesium sulfate requires at least five times dilution for arsenic to quantitatively enter the micellar phase. In the case of calcium gluconate, the organic anion is likely to have a higher affinity for the Triton X-100 phase than molybdoarsenic acid resulting in very low extraction coefficient values. In this case, decomposition of the drug was suggested. Three decomposition methods were evaluated and compared: acid decomposition in an open system, acid decomposition in a microwave reactor, and ashing with MgO/Mg(NO3)2. The second and third methods provide further quantitative removal of arsenic, the second being more rapid and easier to perform.