This standard applies to the determination of zinc content in ammonium metatungstate, with a determination range of 0.0003% to 0.020%. After ammonia analysis, the sample was complexed with tungsten citrate, and the zinc content was determined by the Standard addition method at a wavelength of 213.9 nm by flame atomic absorption spectroscopy (AAS). The standard specifies the preparation of reagents, the use of instruments and the analysis steps to ensure the accuracy and reliability of the measurement results.