Determination of trace elements in high-purity molybdenum by solid-phase extraction/ICP-MS

We attempted a simple pretreating method consisting of solid-phase extraction using bonded silica gel with benzenesulfonic acid (SCX) as the solid-phase sorbent to determine trace elements in pure molybdenum samples by means of inductively coupled plasma mass spectrometry (ICP-MS). Molybdenum was anionized by adding hydrogen peroxide solution to a sample decomposed with acid, and separated from cation trace impurities that had been kept in the chemically bonded silica gel of the ion-exchange type. The target elements retained in the solid phase were eluent with a small amount of dilute nitric acid. In this method, some trace elements, such as Be, Al, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Cd, In, Tl, Ph and Bi were determined by ICP-MS using the eluate. The detection limit (3 sigma), as follows: Be : 0.028, Al : 2.64, Mg : 1.99, Cr : 0.20, Mn 0.13, Fe : 3.85, Co : 0.019, Ni : 0.48, Cu : 0.084, Zn : 0.25, Ga : 0.092, Cd : 0.014, In : 0.059, TI : 0.027, Pb : 0.044 and Bi 0.012 ng/g(ppb).