Colorimetric Determination of Calcium Ion with o-Cresolphthalein Complexone Studies on the Automatic Analysis of Salt Manufacturing Samples (Part5)

• Published in: Bulletin of the Society of Sea Water Science, Japan Vol. 35; no. 1; pp. 33 - 37
• Main Authors: KANOU, Takahiro, SUGITA, Shizuo
• Format: Journal Article
• Language: Japanese
• Published: The Society of Sea Water Science, Japan 1981
• ISSN: 0369-4550; 2185-9213
• DOI: 10.11457/swsj1965.35.33

The authors made an investigation on Technicon's auto-analyzer by the colorimetric method o-cresolphthalein complexone (o-C.P.C.) reagent to determine automatically the calcium ion of salt manufacturing samples. The analytical method was as follows: After the pH of a sample was controlled with potassium phosphate solution (buffer solution), the o-C.P.C.reagent was added to the sample solution, and then a colored complex was formed. Calcium ion was determined by measuring the color intensity. In this method, a linear relationship was obtained between the absorbance and the concentration of calcium ion in the range of 0-200mg/l. This method has the same accuracy as the conventional EDTA method.The coefficient of varia-tion was below 4%, and the speed of analysis was consecutive 20 samples per hour.