T(3—M—4HP)P双峰双波长分光光度法测定镉(Ⅱ)

Determination of Trace Cadmium by Using T(3-M-4HP)P and Dualwavelength Spectrophotometry

本文研究了试剂α、β、γ、δ—四(3—甲氧基—4—羟基苯基)卟啉[T(3—M—4HP)P]与Cd(Ⅱ)的显色反应.在吐温—80和氯代十四烷基吡啶(TPC)存在下,用咪唑作辅助络合剂,在pH10.2～11.2时,Ca(Ⅱ)与T(3—M—4HP)P形成1∶2的稳定配合物。用双峰双波长法测定痕量Cd(Ⅱ)具有很高的灵敏度,ε=5.63×10~5L·mol·cm^(-1).Cd(Ⅱ)浓度在0～3.5μg/25ml范围内符合比尔定律.应用本法测定矿样中的痕量镉,结果满意.

In this paper,the color reaction of Cadmium（I）witha,β,γ,δ-tetra（3-methoxy-4-hydroxyphenyl）porphine（T（3-M-4-HP）P）is studied. In the presence of nonionic surfactant tween-80 and cationic surfactant TPC,with the help of midazol, the Cd（II）-T（3-M-4HP）P complex is formed in a buffer solution of pH 10.2～11.2. The determination of trace cadmium with dualwavelength spectrophotometry is described and the molar absorptivity is equal to 5. 63×105L·mol-1cm-1. The Beer’ s law is obeyed in the range of 0～3. 5μg/25ml. The method has been applied to the determination of the cadmium in ores with satis factory results.