三乙醇胺增敏火焰原子吸收光谱法测定地质样品中的钼

样品经王水分解,加入适量的三乙醇胺增敏,用空气-乙炔火焰原子吸收光谱法测定地质样品中的钼。选择了三乙醇胺的最佳用量;比较了钼在盐酸-磷酸-铝盐、盐酸-三乙醇胺、盐酸-三乙醇胺-磷酸、盐酸-三乙醇胺-磷酸-铝盐等4种不同介质中的特征浓度。结果表明,在盐酸-三乙醇胺-磷酸-铝盐介质中,钼的质量浓度≤40 mg/L内线性良好,方法检出限为0.2 mg/L,相对标准偏差为5.2%(n=6),加标回收率为96%~102%。对国家一级标准物质进行测定,结果与标准值相符。

Determination of Molybdenum in Geological Samples by Triethanolamine Sensitizer-Air Acetylene Flame Atomic Absorption Spectrometry

The geological sample was decomposed by aqua regia and suitable amount of triethanolamine (TEA) sensitizer was added in the sample solution. Molybdenum in the sample was then determined by air-acetylene flame atomic absorption spectrometry. The dosage of triethanolamine was optimized through experiments. The characteristic concentration of molybdenum in four different kinds of media including HCl-H_3PO_4-AlCl_3, HCl-TEA, HCl-TEA-H_3PO_4 and HCl-TEA-H_3PO_4-AlCl_3 was investigated. The results showed that in the HCl-TEA-H_3PO_4-AlCl_3 medium, a wide dynamic linear range was obtained with Mo concentration up to 40 μg/mL. The detection limit of this method is 0.2 mg/L for Mo. The recovery of standard addition is 96%～102% with precision of 5.6% RSD (n=6). The method has been applied to the determination of Mo in national primary standard reference materials and the results are in good agreement with the certified values.