Part 10 of this standard specifies a method for the determination of oxidation manganese content in rare earth chloride and light rare earth carbonic acid. This method is suitable for samples with manganese oxidation content in the range of 0.0020% to 0.20%. The method uses flame atomic absorption spectroscopy (AAS) method. After the sample is dissolved by nitric acid, in a dilute acid medium, the manganese Absorption is measured at a wavelength of 279.5 nm with an air-acetylene flame. The manganese oxidation content is calculated according to the Standard addition method. The standard also details the preparation method of the required reagents, including hydrogen peroxide, nitric acid, muriatic acid and the preparation of manganese standard solution.