Determination of molybdenum in geological sample by flame atomic absorption spectrometry with perchloric acid-sucrose medium
The accurate and rapid determination of molybdenum content in geological samples is of great sig-nificance for the development and utilization of molybdenum ore,geological scientific research,and many other fields.Since molybdenum is an element which is hardly ionized,the determination method by flame a-tomic absorption spectrometry(FAAS)usually has low sensitivity and high limit of detection.The sampling of redox system can increase the air-acetylene flame temperature,thus enhancing the absorbance sensitivity of molybdenum.On the basis of this principle,a method for the determination of molybdenum(0.002%)in geological samples by FAAS was established using perchloric acid as the oxidant and sucrose as the reduc-ing agent.Under the optimized experimental conditions,the mass concentration of molybdenum in range of 2-20 μg/mL had a good linear relationship with the corresponding absorbance,with a correlation coefficient of 0.999 8.The sensitivity was 0.010 6 mL/μg,the limit of detection was 0.000 7%,and the limit of quan-tification was 0.002%.The content of molybdenum in certified reference materials of molybdenum ore for composition analysis was determined according to the experimental method.The maximum relative error between the found results and the certified values were all less than the relative error tolerance(YB)speci-fied in DZ/T 0130-2006 The Specification of Testing Quality Management for Geological Laboratories.The relative standard deviations(RSD,n=9)of the determination results were between 1.5%and 8.2%.