Paints and varnishes — Determination of "soluble" metal content — Part 4: Determination of cadmium content — Flame atomic absorption spectrometric method and polarographic method

The principle of the AAS method consists in inspiration of the test solution into an acetylen/air flame. Measurement of the absorption of the selected spectral line emitted by a cadmium hollow-cathode or cadmium discharge lamp, in the region of 228,8 nm. The principle of the polarographic method consists in electrolysis of the test solution in a polarographic cell measurement of the corresponding heigth of the potential step. The method are applicable to coating materials having "soluble" cadmium contents in the range of about 0,05 % (m/m) to 5 % (m/m). The AAS method should be used as the referee method in cases of dispute. This second edition cancels and replaces ISO 3856/4-1980.