Direct determination of trace elements in niobium,tantalum and their oxides by inductively coupled plasma atomic emission spectrometry after microwave dissolution

Analytical schemes for the determination of trace elements in high-purity niobium, tantalum and their oxides are proposed. The schemes are based on microwave dissolution of the metals and oxides followed by inductively coupled plasma atomic emission spectrometry (ICP-AES) determination of impurities in the solutions. The possibilities of interelement and off-peak background corrections in ICP-AES analysis are discussed. The accuracy of the results obtained is confirmed by the determination of trace elements after a matrix sorption separation procedure. For a number of elements, a comparison of the results obtained by ICP-AES without and with the matrix separation procedure and by electrothermal atomic absorption spectrometry (ETAAS) shows good agreement. The limits of detection for direct ICP-AES determination are in the range 0.4*1.0 μg g^?1 for Ba, Ca, Fe, Mg, Mn, Y and La; between 2.0 and 10.0 μ g^?1 for B, Cd, Co, Cr, Cu, Hf, Mo, Na, Nb, Ni, Pb, Sr, Ti, Zr and Ta; and for K, Sb and W a detection limit of 20 μ g^?1 is achieved. The schemes proposed are intended for rapid routine analysis.