Automatic Determination of Water Hardness by Vector Colorimetry with Acid Chrome Blue K

• Published in: Journal of analysis and testing Vol. 7; no. 2; pp. 157 - 162
• Main Authors: Gao, Su, Ye, Ming-Liang, Ma, Rui, Liu, Ai-Rong, Gao, Hong-Wen
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.06.2023
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Monitoring/Environmental Analysis; Original Paper; Acid chrome blue K; Total hardness; Online automatic detection; Vector chromaticity measuring device
• ISSN: 2096-241X; 2509-4696
• DOI: 10.1007/s41664-022-00230-2

Based on the Mg 2 + complexation with acid chrome blue K (ACBK) at pH 10.2, an automatic system was designed to determine total hardness of water. The system consists of a vector colorimeter, a multi-channel sampling pump and both reagents A and B. Two kinds of reagent solutions were prepared and used in this system, i.e., ammoniacal buffer and ACBK—disodium magnesium EDTA solutions. The experimental results of the standard solutions containing 2 and 3 mg/L of total hardness showed that the relative standard deviations (RSDs) were 1.9% and 2.2%, respectively, and the limit of detection (LOD) was only 0.035 mg/L. The detection of four natural water samples showed that the recoveries were between 85.0% and 108.6%, consistent with those obtained by ICP-AES method.