微乳液介质二溴羟基苯基荧光酮光度法测定维生素B_(12)中的钴

Spectrophotometric Determination of Cobalt in Vitamin B 12 with DBH-PF in Microemulsion

研究了钴与二溴羟基苯基荧光酮在溴化十六烷基吡啶—乳化剂ＯＰ复配型微乳液介质中的显色反应，钴与ＤＢＨ—ＰＦ在ｐＨ１０．５的硼砂—氢氧化钠缓冲溶液中，形成１３的稳定配合物．配合物的最大吸收波长为６４０ｎｍ，表观摩尔吸光系数为１．９×１０５Ｌｍｏｌ－１ｃｍ－１，钴量在０～６ｍｇ／１０Ｌ范围内符合比尔定律．本法采用巯基葡聚糖凝胶分离共存离子富集钴，提高了方法的选择性，使方法的检测限降低．该法用于维生素Ｂ１２样品的测定，结果准确可靠．

In this paper,the color reaction of cobalt with 2,6,7 trihydroxy 9 (3,5 dibromo 4 hydroxyphenyl)fluorone(DBH-PF) in microemulsion has been studied.Cobalt(Ⅱ) reacts with DBH-PF to form a stable 1∶3 complex at pH10 5.Its apparent molar absorptivity is 1 9×10 5L·mol -1 ·cm -1 at 640nm.Beers law is obeyed in the range of 0～6mg/10L for cobalt(Ⅱ).The common metal ions can be separated,and cobalt can be enriched by sulfhydryl dextran gel(SDG),greatly improving the selectivity and sensitivity of the system.The method has been used to determine cobalt in vitamin B 12 with satisfactory results.