ISO 6678:1981

Phosphoric acid for industrial use — Determination of lead content — Atomic absorption spectrometric method

The lead is extracted from a diluted test portion into a solution of diethylammonium diethyldithiocarbamate in xylene. The xylene extract is separated and aspirated into the acetylene/air flame of an atomic absorption spectrometer. The spectrometric measurements are carried out at a wavelength of about 217 nm or, alternatively, about 283 nm. The method is applicable to phosphoric acids having lead contents greater than 0.1 mg/kg.