本文以偶氮胂Ⅲ为显色剂,建立了钙的分光光度测定法。偶氮胂Ⅲ与钙在pH6.5六次甲基四胺介质中形成紫蓝色配合物,其组成M:R=1:2,采用两个吸收峰,其测定波长分别为602nm、652nm,表观摩尔吸光系数ε=4.2×10~4L·mol~(-1)·cm~(-1),钙量在1.25～30.0μg/25ml符合比耳定律。回收率在96.3％～103.3％,变异系数在0.93％～3.72％之间。当乙醇含量为24％时,比水溶液提高了33％。并 In this paper, arsenazo Ⅲ as a reagent, the establishment of a calcium spectrophotometry. Arsenazo III and calcium form a violet-blue complex in pH 6.5 hexamethylenetetramine media with a composition of M: R = 1: 2 and two absorption peaks at 602nm, 652nm, The apparent molar absorptivity ε = 4.2 × 10 ~ 4L · mol -1 · cm -1, and the calcium content of 1.25 ~ 30.0μg / 25ml accords with Beer’s law. The recoveries ranged from 96.3% to 103.3% and the coefficients of variation ranged from 0.93% to 3.72%. When the ethanol content is 24%, it is 33% higher than the aqueous solution. and