Meso-四( 4-甲氧基-3-磺酸苯基) 卟啉 与钴的显色反应及其钴的价态研究

本文研究了在弱酸性介质中,Co(Ⅱ)与 T( 4 -MO-3-SP) P 的显色反应. 当溶液 pH 为 4. 15 时, 显色剂 和配合物的最大吸收峰分别在 440. 0nm 和 427. 0nm. 显色反应完全后, 经酸化, pH 为 2. 65, 配合物不分 解,最大吸收峰不位移. 实验证明, 钴以二价态参与反应. Co(Ⅱ)与 T( 4 -MO-3-SP) P 的配位比为 1∶ 1, Co (Ⅱ)含量在 0～ 3. 0μ g/25m L 范围内符合比耳定律, 摩尔吸光系数 ε=1. 95×105L·mol-1·cm-1, 回归方 程 y =0. 009933 +0. 1222x, 相关系数 r = 0. 9991. 实验测定 VB12针剂中 Co(Ⅱ)含量 ,结果满意.

Study on the Spectrophotometric Determination of Cobalt with Meso-T( 4-MO-3-SP) P and Its Valence Species

The condition of the color reaction meso-T( 4-phexamethoxy-3-sulfophonyl)porphyrin w ith cobalt were studied at pH4. 15. It has been show n that the maximum absorption wavelengths of the reagent and the complex respectively are 440nm and 427nm. After color reaction finished, the system was acidify to pH 2. 63,the complex can not be resolved. The results show that the ion of reaction w ith porphyrin is cobalt(Ⅱ). The coordination ratio of Co(Ⅱ)to T( 4 -MO-3-SP) P is 1∶ 1. The apparent molar absorption coefficient is 1. 95×105L·mol-1·cm-1. Beer' s law is obey in concentration range of 0～ 3. 0μ g/25mL. This method has been applied to the determination of micro Co(Ⅱ)in vitamin B12 . The results are favorable agreed with that obtained by AAS.