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目的:为杂粮中痕量铈的测定建立一种新的方法。方法:研究了偶氮硝羧与Ce(Ⅲ)的光谱变化、反应条件、表面活性剂及共存离子的影响。结果:紫红色染料偶氮硝羧在pH5.76的HAc-NaAc缓冲介质中能与Ce(Ⅲ)发生选择性和灵敏度高的β型反应,形成稳定的蓝色配合物,λmax为730nm,比试剂本身的545nm红移185nm。铈含量在0~1.54μg/mL范围内符合比尔定律,表观摩尔吸收系数为4.94×104L/mol·cm。建立了铈测定的光度新方法,结论:建立的方法操作简便快速,用于杂粮中Ce(Ⅲ)含量测定,结果满意。
Objective: To establish a new method for the determination of trace cerium in cereals. Methods: The spectral changes of azobenzene and Ce (Ⅲ), reaction conditions, surfactants and coexisting ions were studied. Results: Azure nitrate could react with Ce (Ⅲ) in the HAc-NaAc buffer medium of pH5.76 with high selectivity and sensitivity to form a stable blue complex with a λmax of 730nm. Reagents of the 545nm red shift 185nm. Beer’s law is obeyed in the range of 0-1.54 μg / mL for cerium, and the apparent molar absorption coefficient is 4.94 × 104 L / mol · cm. The new method of determining the luminosity of cerium was established. Conclusion: The established method is simple and rapid in operation and is suitable for the determination of Ce (Ⅲ) content in cereals. The results are satisfactory.