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-H3PO4-AlCl3, HCl-TEA, HCl-TEA-H3PO4 and HCl-TEA-H3PO4-AlCl3was investigated. The results showed that in the HCl-TEA-H3PO4-AlCl3 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.