高灵敏度分光光度法同时测定钴和钯  

Highly Sensitive Spectrophotometric Simultaneous Determination of Cobalt and Palladium

作　　者：刘根起[1] 程永清[1] 张光[2] 

机构地区：[1]西北工业大学化学工程系,陕西西安710072 [2]陕西师范大学化学系,陕西西安710062

出　　处：《光谱学与光谱分析》2003年第5期1021-1023,共3页Spectroscopy and Spectral Analysis

摘　　要：提出用5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯分光光度法同时测定钴和钯的新体系. 室温下, 钴与试剂仅能在pH 5.0～6.5范围内定量反应, 加酸酸化后, 其最大吸收波长红移至586 nm, 且灵敏度高提高; 而钯与试剂于强酸性介质中即可显色完全, 其最大吸收波长位于592 nm. 在589 nm处, 钴、钯配合物的吸光度具有良好的加和性, 其摩尔吸光系数分别为1.41×105 L·mol-1·cm-1和1.11×105L·mol-1·cm-1. 基于二者显色反应的酸度差异, 建立了钴、钯同时测定的新方法. 钴、钯浓度分别在0～0.36 mg·L-1和0～ 1.5 mg·L-1内服从比耳定律. 所拟方法已成功用于矿样中钴、钯的同时测定.A new highly sensitive system for spectrophotometric simultaneous determination of trace cobalt and palladium with 5- (5-nitro-2-pyridylazo) -2, 4-diaminotoluene ( 5-NO2-PADAT) has been developed. The system. is based on the different acidities required by complex formation reactions between the two kinds of metallic ions and 5-NO2-PADAT. At room temperature, Pd can react with 5-NO2-PADAT quantitatively in strong acid medium, while Co can react with 5-NO2-PADAT only in HAC-NaAC buffer solution of pH 5.0-6. 5 and the Co complex formed can be changed into another stable blue species of higher sensitivity by the addition of mineral acid. The lambda(max) of the complexes of Co and Pd are at 586 and 592 mn respectively. At 589 mn, the absorption of the complexes of Co and Pd shows a very good spectral additive property, and the epsilon(Co) and epsilon(Pd) are 1.41 x 10(5) L (.) mol cm(-1) and 1. 11 x 10(5) L (.) mol(-1) (.) cm(-1) respectively. Beer's law is obeyed in the ranges of 0-0.36 mg (.) L-1 for Co and 0-1.5 mg (-1) for Pd. The method has been proved to be successful for the simultaneous determination of Co and Pd in ores.

关 键 词：高灵敏度分光光度法 同时测定 钴 钯 5-(5-硝基-2-吡啶偶氮)-2 4-二氨基甲苯分光光度法 

分 类 号：O614.812[理学—无机化学] O657.32[理学—化学]