系数倍率双波长标准加入法同时测定铜和锌

SIMULTANEOUS DETERMINATION OF COPPER AND ZINC BY K _FACTOR DUAL_WAVELENGTH STANDARD ADDITION METHOD

以２＿（５＿溴＿２＿吡啶偶氮）＿５＿二乙氨基苯酚为显色剂，乳化剂ＯＰ为增溶剂，根据系数倍率双波长标准加入法原理，建立了一种同时测定铜和锌的新方法．测量时以５５５ｎｍ为测定波长，５７５ｎｍ为参比波长，测得吸光度，然后按方法原理处理测量数据并作图求得铜、锌的含量．当铜∶锌（重量比）在１∶１～１∶２０范围内时，测量的回收率在９５％～１１０％，应用于人发中铜、锌含量的同时测定，获得了满意的结果．

A new method for the simultaneous spectrophotometric determination of copper and zinc is proposed. The method is based on the difference of absorption spectra of copper and zinc forming coloured complexes with 5_Br_PADAP in weak acidic medium and in the presence of nonionic surfactant OP. The absorbances of complex solution are measured at wavelength of 555 and 575 nm, respectively, and the data treated by the principle of K _factor dual_wavelength standard addition method. The recovery rate of both elements is found to be 95%～110% in the synthetic mixtures containing microamounts of copper and zinc with the concentration ratio from 1∶1 to 1∶20. The proposed method has been applied to the determination of copper and zinc in human hair with satisfactory results.