Study on Elimination of Matrix Interference in Determination of 12 Trace Elements in Ammonium Molybdate by Inductively Coupled Plasma Mass Spectrometry

Accurate determination of trace impurities in ammonium molybdate is the key to product quality control. In order to provide reliable data support for the quality testing and product control of ammonium molybdate, the contents of trace elements Mg, Al, Ca, Cr, Fe, Mg, Ni, Cu, As, Cd, Sd and Pb in ammonium molybdate were analyzed by online internal standard-inductively coupled plasma mass spectrometry (ICP-MS). The samples were dissolved in hydrochloric acid-nitric acid-hydrofluoric acid. The effectiveness of aerosol dilution, matrix matching and online internal standard methods for matrix interference elimination were compared. Finally, an online addition of multiple internal standards was used to eliminate the interference caused by the high purity molybdenum matrix. The results showed that the linear correlation coefficients were all greater than 0.9990, the limits of detection were 0.008 ~ 0.2 μg/g, the relative standard deviations were 0.10% ~ 0.38%, the recoveries were in the range of 90% ~ 108%, and the matrix effect was effectively eliminated. At the same time, the samples were sent to the authoritative external inspection agency, and the test results were within the allowable range, indicating that the method had a high accuracy and good precision, and met the requirements for accurate detection of trace impurity elements in ammonium molybdate products on the market.