[Determination of urinary lead through optic emission spectrography using the double-arch method].
A new method for the determination of urinary lead by means of the emission spectroscopy is described. The sample is concentrated by lyophilization and the homogeneous dust obtained is analysed using the "double arc" method. The matrix effects and the source unstability are compensated by the use of the internal standard. The influence of the volatilization of the elements of the analytical pairs are studied and the pair thallium-lead is selected. The method is reproducible and the detection limit is 5 microgram/l of urinary lead.