Determination of lead at the ng ml-1 level by reduction to plumbane and measurement by inductively-coupled plasma emission spectrometry

A detection limit of 1 ng ml^-1 for lead is obtained by the reported method. Samples are prepared in 0.5 M hydrochloric acid—0.8 M hydrogen peroxide. Plumbane is produced (with 64% efficiency) by the addition of 5% sodium tetrahydroborate in 0.5% NaOH, and is transported by the argon feed directly to an inductively-coupled argon plasma for emission spectrometry. Decreased hydrogen generation and greater stability of the plasma also contribute to the improved detection limit. The method is shown to be generally applicable to As, Sb, Bi, Sn, Te and Se, with detection limits at the ng ml^-1 level.