Development of Accurate Concentration Calibration Techniques aimed at Supplying Anionic Surfactants Mixture Standard Solution Based on Japan Calibration Service System

Abstract

Anionic surfactants are among the water quality test items under the purview of the Water Supply Act. The provision of mixed standard solutions of five types of alkylbenzene sulfonates (ABS) within the Japan Calibration Service System (JCSS) has been desired. However, achieving SI traceable characterization has been challenging due to the target analytes being ABS with varying alkyl chain lengths (C10-C14) and each ABS being a mixture of structural isomers. In this study, we developed an SI traceable characterization method for the total concentration of each ABS isomer, leveraging their uniform molar absorptivity. Additionally, we developed a method to accurately characterize mixed solutions (Secondary standard solutions) using mixed solutions (Specified standard solution: Primary standard solution in the Measurement Act) with peak area corrections derived from single-component solution measurements. The JCSS anionic surfactant mixture standard solution supplied by this method is reliable for use as calibration solutions in the measurement of water quality standards under the Water Supply Act.