用三刺激比色法评估在乙二胺四乙酸（EDTA）滴定镍（II）过程中络合指示剂的颜色质量。

Evaluation of colour quality of complexometric indicators in the titration of Nickel(II) with EDTA by tristimulus colorimetry.

作者信息

Raheem S, Prasad K M

机构信息

School of Chemistry, Andhra University, Visakhapatnam 530 003, India.

出版信息

Talanta. 1993 Dec;40(12):1809-14. doi: 10.1016/0039-9140(93)80100-6.

DOI:10.1016/0039-9140(93)80100-6

PMID:18965855

Abstract

Trichromatic colorimetry was applied to the specification of colour changes of metallochromic indicators viz., murexide, pyrocatechol violet, bromopyrogallol red, pyrogallol red and chromazurol S in the complexometric titration of Nickel(II) with ethylene-diaminetetraacetic acid (EDTA), in order to assess the quality of colour change at the equivalence point with the help of CIE Lab* 1976 system and the values of SCD (Specific Colour Discrimination) parameter. A screened indicator, a mixture of murexide and methylene blue in the ratio 10:1 (m/m), is proposed as an ideal indicator in this titration as evidenced by the plots of a* vs. b* and from the numerical values of standard deviation for a large number of visual titrations.

摘要

采用三色比色法测定在镍（II）与乙二胺四乙酸（EDTA）络合滴定中金属变色指示剂（即紫脲酸铵、邻苯二酚紫、溴邻苯三酚红、邻苯三酚红和铬天青S）的颜色变化，以便借助CIE Lab* 1976系统和特定颜色辨别（SCD）参数值评估等当点处颜色变化的质量。通过a对b的曲线以及大量目视滴定的标准偏差数值证明，一种筛选出的指示剂，即紫脲酸铵与亚甲基蓝按10:1（质量比）混合的混合物，被提议作为该滴定的理想指示剂。