The principle of the method specified is dissolution of a test portion in nitric acid, measurement of the absorption of the resonance line energy from the spectrum of lead in the test solution at a wavelength of 283,3 nm by an atomic absorption spectrometer fitted with a graphite furnace electrothermal atomizer, calibration by the standard additions method described in ISO 11438-1. Applies to lead contents in the range of 1,0 g/t to 5,0 g/t in ferronickel.