化学发光-流动注射-胶束增敏连续测定钴铬研究

Chemiluminescence Flow Injection Method for the Consecutive Determination of Cobalt and Chromium

基于钴（Ⅱ）和铬（Ⅲ）对鲁米诺－过氧化氢化学发光反应均有催化作用，加入ＣＴＭＡＢ能明显提高发光的信噪比，可测定亚纳克量的钴和铬，加入ＥＤＴＡ掩蔽钴（Ⅱ）测得铬（Ⅲ）量，再由钴和铬总量求得钴（Ⅱ）量，实现钴和铬的不经分离而流动注射连续测定。此法线性范围宽达４个数量级（１０－１１～１０－７ｇ／ｍＬ），检测下限低（Ｃｏ２＋１．２×１０－１１ｇ／ｍＬ，Ｃｒ３＋１．０×１０－１１ｇ／ｍＬ），再现性好，工效高（１２０个样品／ｈ），用于三种矿泉水中痕量钴（Ⅱ）、铬（Ⅲ）连续测定。

A chemiluminescence flow injection method for the consecutive determination of cobalt and chromium is described. It is based upon the catalytic effect of these metallic ions on luminol oxidation by hydrogen peroxide. The chemiluminescence signal to noise ratio can be enhanced by the addition of cetyl trimethylammonium bromide(CTMAB).Subnanograms of cobalt and chromium can be determined together. After the addition of EDTA to mask Co(Ⅱ),Cr(Ⅲ) can be determined.The amount of cobalt can be obtained by subtracting the amount of chromium from the total amount of Co+Cr.The method has a wide linear range(10 11 ～10 7 g/mL), chromium low detection limit (1.2×10 11 g/mL for Co,and 1.0×10 11 g/mL for Cr),good reproducibility,and rapidity(120 runs/h).It has been satisfactorily applied to the analysis of three kinds of mineral water in China.