GB/T 13884-2003 requires atomic absorption spectroscopy (AAS) for the determination of cobalt content in feed. The feed sample is first processed to dissolve the cobalt element and convert it into a solution. Absorbance is determined by AtomicAbsorption Spectroscopy based on the absorption characteristics of cobalt atoms to specific wavelengths of light. The content of cobalt in feed is accurately calculated by the standard Linear dispersion method. The standard provides a reliable method for mass detection of feed, ensures that the cobalt content in feed meets regulations, and protects animal health. It is widely used in feed production, Quality control and other links, and was later revised.