新试剂2,7-双(5-羧基-1,3,4-三氮唑偶氮)-变色酸作为络合滴定铜指示剂的研究

Studies on 2,7-Bi(5-Carboxy-1,3,4-Triazolylazo)-Chromotropic Acid Indicator for Copper in Complexometric Titration

研究了新试剂2,7-双(5-羧基-1,3,4-三氮唑偶氮)-变色酸(简称BCTZACA)作为络合滴定铜的指示剂的分析性能。在pH4.5-6.0范围内,加入8滴BCTZACA指示剂,用EDTA标准溶液进行络合滴定,终点由蓝色变为橙黄色,变色敏锐,准确度高,用于试剂样品和合金中铜的测定,结果与标准值相符,RSD(n=6)为0.11%-0.45%。

2, 7-bi (5-carboxy-1, 3, 4-triazolylazo)chromotropic acid (BCTZACA) as a new indicator for copper in complexometric titration was studied. In buffer solution ofpH 4. 5-6.0,copper was titrated by EDTA with 8 drops of BCTZACA indicator, a sharp color change from blue into gamboges at the end point was obtained.The method was applied to the direct determination of copper in the reagent sample and alloy with identical result to the reference value. The RSD is in the range of 0. 11%-0. 45%(n=6).