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光度法测定微量钴已有不少报道。但大多不甚完美,在实际应用中有一定的限制。2—(5—溴—2—吡啶偶氮)—5—二乙氨基酚(简称 5—Br—PADAP)是高灵敏度金属显色剂,应用于钴的测定已有报道,但其水溶性差,显色稳定性欠佳。本文在此基础上采用OP作为胶束增溶稳定剂,提高了显色的稳定性和方法的灵敏度。同时控制显色反应前后的酸度,提高了选择性。结果表明络合物最大吸收波长为590nm,钴的浓度在0～20μg/25ml符合比耳定律,表观摩尔吸光系数ε_(590)=7.3×10~4L·mol~(-1)cm~(-1)。本法选择性好,灵敏度高,方法简便。用于矿泉水及饮用水中微量钴的测定,结果满意。
Spectrophotometric determination of trace cobalt has been reported. But most are not perfect, there are some restrictions in practical application. Bromophenol (referred to as 5-Br-PADAP) is a highly sensitive metal developer. The determination of cobalt has been reported, but its solubility in water is poor. Poor color stability. Based on this, OP was used as micellar solubilizing stabilizer to improve the stability of coloration and the sensitivity of the method. At the same time control the color of the acidity before and after the reaction to improve the selectivity. The results showed that the maximum absorption wavelength of the complex was 590nm and the cobalt concentration was 0 ~ 20μg / 25ml. Beer ’s law was obeyed. The apparent molar absorptivity ε_ (590) = 7.3 × 10 ~ 4L · mol ~ (-1) cm ~ -1). This method is good selectivity, high sensitivity, simple method. For mineral water and drinking water trace cobalt determination, the results are satisfactory.