Paints and varnishes — Determination of "soluble" metal content — Part 2: Determination of antimony content — Flame atomic absorption spectrometric method and Rhodamine B spectrophotometric method

The methods are applicable to coating materials having "soluble" antimony 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. The principle of the flame atomic absorption spectrometric method consists in aspiration of the test solution into acetylen/air flame. measurement of the absorption of the selected line, amitted by an antimony hollow-cathode or antimony discharge lampe. The principle of the Rhodamine B spectrophotometric method consists in extraction of the antimony after oxidation from strong hydrochloric acid solution with di-isopropyl ether. Formation of a red complex with Rhodamine B solution, and spectrophotometric measurement of the colour at a wavelength of about 553 nm.