This standard specifies a method for the determination of mg content in nickel by flame atomic absorption spectroscopy (AAS), which is applicable to the determination of mg content in nickel in the range of 0.0005% to 0.002%. Method Absorbance measurement of mg at wavelength 285.2 nm is carried out by using an air-acetylene flame in a dilute nitric acid medium after analysis of the sample with nitric acid. The standard describes in detail the preparation of the reagent, the analysis steps and the use conditions of the instrument to ensure the accuracy and precision of the measurement results, providing a reliable technical basis for the detection of trace mg in nickel.