The determination of lithium, sodium and potassium in geological materials by atomic-emission spectrophotometry with the nitrous oxide-acetylene laminar-flow flame

Abstract

A straightforward method is described for the determination of lithium, sodium and potassium by atomic-emission spectrophotometry on an acidic solution of the sample without separation or concentration. In routine application detection limits of 0·002, 0·01 and 0·01 per cent., respectively, have been obtained with no spectral or chemical interferences. Results are presented for eight standard samples, and long-term relative standard deviations of 2·4 per cent. (lithium), 1·7 per cent. (sodium) and 2·5 per cent. (potassium) have been found on a B.C.S. firebrick.

By using wavelength scanning the determination of trace amounts of lithium has been demonstrated, with a detection limit of about 0·1 p.p.m. in the sample. If blank problems can be controlled the direct determination of sodium and potassium at the parts per million level should be possible even for limestones.