邻苯二酚紫高灵敏显色反应的研究

Study on Sensitive Colour Reaction of Pyrocatechol Violet

在溴化十六烷基三甲基铵(CTMAB)存在下,以抗坏血酸(AA)和氯乙酸(CAA)为辅助配位体,在pH0.9～1.6范围内邻苯二酚紫同锡(PV)形成多元PV—Sn(IV)—AA—CTMAB配位显色体,使PV作为光度试剂达到迄今为止最高的摩尔吸光系数—ε_(662)=1.43×10~5L·mol^(-1)·cm^(-1)。锡浓度在范围服0.02～0.7ppm从比尔定律。方法可直接用于锌合金和铜合金中微量锡的测定。

In the presence of cetyltrimethylammonium bromide （CTMAB） sue ascorbic acid （AA） and chloroacetic acid （CAA） as auxiliary complexing agents, in the range of PH 0.9 to 1.6 pyrocatechol violet （PV） with tin （Ⅳ） formed a colour-producing reaction system of multicomponent coordination complexes PV-Sn （Ⅳ） -AA-CAA-CTMAB, the sensitivity for PV as a spectrophotometric agent is highest (ε662=1.43×105L. mol-1. cm-1). The compsition of complexes for the main component parts is Sn （Ⅳ）:PV:CTMAB=1:2:2. Beer’s law is obeyed for 0.02 to 0.7 ppm of Sn （Ⅳ）. This means may be applied to the determination of tin in some zinc or copper base alloy.