meso-四[3,5-二(三氟甲基)苯基]卟啉与镉的显色反应研究

Study of chromogenic reaction of cadmium with meso-tetrakis [3,5-bis (trifluoromethyl) phenyl] porphyrin

研究了新合成显色剂meso 四 [3,5 二 (三氟甲基 )苯基 ]卟啉 [T( 3,5 DTFMP)P]光度法测定痕量镉 (Ⅱ )的方法与应用。试验表明 ,在pH 1 0 .6的缓冲液、Tween 80及邻菲口罗啉介质中 ,经沸水浴加热 7min ,显色反应完全 ,Cd(Ⅱ )量在 0～ 3μg/2 5mL范围内具有线性关系 ,表观摩尔吸光系数ε442 为 2 1 9× 1 0 5L·mol- 1 ·cm- 1 。显色体系不经掩蔽可直接测定烟草中的痕量Cd(Ⅱ) 。

Meso-tetrakis [3,5-bis (trifluoromethyl) phenyl] porphyrin [T(3,5-DTFMP)P] for the spectrophotometric determination of trace cadmium has been studied. The experimental results showed that the reaction was completed by heating at 100 ℃ for 7 min in an alkaline solution of pH 10.60. It was a sensitive and selective chromometric reagent for the direct determination of cadmium in the presence of Tween-80 and o-phenanthroline. Its apparent molar absorptivity ε_(442) is 2.19×10~5 L·mol^(-1)·cm^(-1). Beer′s law is obeyed in the range of 0～3 μg of per 25 mL. This method has been successfully applied to the determination of cadmium in tobacco.