定量分析中的络合滴定实验,一般是用铬黑T(EBT)作指示剂测钙、镁离子总量.由于铬黑T水溶液不稳定,通常与氯化钠配成固体溶液使用.由于难于掌握用量,平行试样颜色深浅不一,是产生误差的原因之一. 用乳化剂OP~*和铬黑T配制成水溶液,其中OP浓度为1%,铬黑T浓度为10~(-3)M.这样的水溶液稳定性强,放置二个月后让学生使用,结果与使用铬黑T固体溶液的数据对比如下: Quantitative analysis of complexometric titration experiments, the general use of chromium black T (EBT) as an indicator of total calcium and magnesium ions due to instability of aqueous solution of chromium black T, usually dubbed solid solution with sodium chloride due to the difficulty It is one of the causes of the error that the error of color is caused by the amount of parallel sample, and the aqueous solution is prepared with emulsifier OP ~ * and chrome black T. The OP concentration is 1%, the concentration of chrome black T is 10 ~ (-3) ) M. The stability of such an aqueous solution, placed two months after the students to use, the results with the use of chromium black T solid solution data is as follows: