卟啉分光光度法测定豆类微量Cu(Ⅱ)含量

Spectrophotometric Determination of Trace Cu(Ⅱ) in Bean with Porphyrin

以meso-四（4-氯-3-磺酸钠基苯基）卟啉为显色剂,采用分光光度法,研究了该试剂与Cu（Ⅱ）络合反应,以及各种因素对吸光度的影响,从而确定了最佳测定条件。在pH条件为5.0、β-环糊精、盐酸羟胺介质中沸水浴加热5 m in,卟啉与Cu（Ⅱ）可完全络合。络合后再加入（1＋1）HC l,在423 nm处测定络合物的吸光度,表观摩尔吸光系数为4.12×10^5L.mol-1.cm-1,线性范围为0～1.2μg/10mL,抗干扰能力强。该法首次应用于测定豆类中微量Cu（Ⅱ）含量,测定结果满意,有利于建立适合小企业采用的微量铜测试方法。

Aiming to develop a spectrophotometric method for determining trace Cu（Ⅱ） in bean with porphyrin as color reagent,the complexing reaction of meso-tetra（4-Chlorol-3-sulfophenyl） porphyrin with Cu（Ⅱ） has been studied by spectrophotometry.The effects of parameters to the absorbency were investigated and the optimal determination conditions were obtained.Results： The reaction conditions are 100 ℃ water bath for 5 min,in medium of β-cyclodextrin,hydroxylamine HCl solution,and pH 5.0.Adding HCl after the complexing reaction,the absorbency at 423 nm is determined. The apparent molar absorption coefficient at 423 nm is 4. 12×10^5 L·mol^-1· cm^-1, linear range is 0 ～ 1.2 μg/10 mL, and the ability of anti -jamming is high. The method is applied for the first time to determine trace Cu （Ⅱ） in bean and the result is satisfied. It would be fit for small business.