ISO International Standard

The reference method described is applicable to products having total mercury contents in the range of about 0.01 % (m/m) to 0.5 % (m/m). May also be extended to products with a total content of more than 0.5 % (m/m). The principle of the method consists in the combustion of the test portion with oxygen in an enclosed system. Reduction of the mercury(II) compounds contained in the resulting solution to elementary mercury. Entrainment of the metal in a gas stream at ambient temperature and determination as the monoatomic vapour by cold vapour atomic absorption spectrometry at a wavelength in the region of 253.7 nm.