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研究了以钴对鲁米诺桑色素 (LAM)氧化的催化反应作为指示反应的测定痕量钴的新方法及表面活性剂对该催化反应的增敏作用。LAM在碱性条件下被H2 O2 氧化褪色 ,钴对该氧化反应有强烈的催化作用。阳离子表面活性剂 ,如CTMAB对此催化反应有较强的增敏作用 ,可将灵敏度提高 4倍。据此建立了测定痕量钴的催化动力学新方法 ,并测定了该催化反应的动力学参数 ,以探讨表面活性剂增敏的机理。方法的检出限为 7.5ng/mL ,相对标准偏差为 4× 1 0 - 3%。用该法测定了维生素B1 2 中钴的质量分数 ,与原子吸收测定结果十分吻合。
A new method for the determination of trace cobalt with the catalytic reaction of cobalt oxidation of luminol pigment (LAM) as an indicator was investigated. The sensitization of surfactant to the catalytic reaction was studied. LAM is oxidized and faded by H2O2 under alkaline conditions, and cobalt has a strong catalytic effect on the oxidation reaction. Cationic surfactants, such as CTMAB have a strong sensitizing effect on this catalytic reaction, which can increase the sensitivity by 4 times. Based on this, a new catalytic kinetic method for the determination of trace cobalt has been established. The kinetic parameters of the catalytic reaction have been determined to investigate the mechanism of surfactant sensitization. The detection limit of the method was 7.5ng / mL, with a relative standard deviation of 4 × 10-3%. The method was used to determine the mass fraction of cobalt in vitamin B1 2, which was in good agreement with the results of atomic absorption spectrometry.