Study of Some Tungsten-Containing Chemical Modifiers in Graphite-Furnace Atomic Absorption Spectrometry

Abstract
Several chemical modifiers based on tungsten have been evaluated: the individual modifiers W(VI) as WO3 in aq. 0.2 M NH3 and W(V) as W in H2O2 and the mixed modifiers W(VI)/NH3 + Pd(II), W(V)/H2O2 + Pd(II), and W(V)/H2O2 + PO4 3-. High efficiency of thermal stabilization for 18 analyte elements of high and moderate volatility has been demonstrated and possible mechanisms of stabilization are discussed.