Paints and varnishes — Determination of "soluble" metal content — Part 1: Determination of lead content — Flame atomic absorption spectrometric method and dithizone spectrophotometric method

The principle of the AAS method consists in aspiration of the test solution into an acetylen/air flame. Measurement of the absorption of the selected spectral line, emitted by a lead hollow-cathode or lead discharge lamp, in the region of 283,3 nm. The principle of the dithizone method consists in extraction of the lead from the test solution with an solution of dithizone in 1,1,1-trichloroethane. Spectrophotometric measurement of the red colour of the lead dithizonate at a wavelength of about 520 nm.