二溴羧基偶氮胂光度法测定铜合金中痕量铋

Spectrophotometric Determination of Trace Bismuth in Copper Alloys with Dibromocarboxyarsenazo

本文研究了二溴羧基偶氮胂(DBC(O)—ASA)与铋的显色反应。实验表明,在0.24mol·L^(-1)HClO_4-0.16mol·L^(-1)H_3PO_4介质中,铋与题示试剂形成组成为1:2的紫红色配合物,最大吸收峰在635nm处,表观摩尔吸光系数为7.27×10~4。铋量在0～60μg·25mL^(-1)范围内符合比尔定律。本法可测定铜合金中的痕量铋。

The colur reaction of bismuth on DEC(O) - ASA has been inves -tigated in 0. 24mol ·L-1 HC1O4 and 0. 16 mol ·L-1 H3PO4 medium. Bismuth reacts on the title reagent to form a 1 : 2 violet -red complex. The appparent molar adsorptivity is 7. 27×104. The experiment conforms to Beer's law when the bismuth concentration rangs from 0 to 60ug ·25mL-1. The method can be used to determine bismuth in copper alloys.