Determination of molybdenum by flame and electrothermal atomisation atomic absorption spectrometry after complexation and sorption on activated carbon

Abstract

A method for the pre-concentration of Mo is proposed. Molybdenum is complexed by the ammonium salt of the dithiophosphoric acid O,O-diethyl ester and sorbed on to activated carbon. After desorption in a small volume of nitric acid solution, Mo is determined by atomic absorption spectrometry using either discrete nebulisation into the flame or the graphite furnace technique. Iron(III) should be reduced to iron(II) before the complexation, if present in relatively high amounts. A high enrichment factor, simplicity and the fact that the complexation takes place at low pH values are real advantages of this procedure. The method was applied to the determination of Mo in biological reference materials and good agreement was obtained with the literature values.