GB/T 7475-1987 Specification Determination of copper, zinc, lead and cadmium in water by Atomic absirption spectroscopy-tometry, AAS. The standard is based on the absorption characteristics of each element to specific wavelengths of light. Clarify the performance requirements of required instruments and equipment, such as atomic absorption spectrophotometer. Detail the collection and storage methods of water samples to prevent element loss or contamination. Describe the sample pretreatment steps, such as digestion methods. Standardize the test process, including instrument commissioning, standard Linear dispersion drawing and water sample determination. According to this standard, the content of copper, zinc, lead and cadmium in water can be accurately detected, which can help water quality monitoring and water pollution prevention and control.