This standard serves as a foundational document for chemical analysis, establishing unified quality specifications and testing methods for water used in laboratory analysis. It categorizes analytical laboratory water into three grades: Grade 1, Grade 2, and Grade 3, each corresponding to distinct purity requirements, preparation methods, and applicable scenarios. Among these, Grade 1 water is intended for analytical tests with stringent requirements, such as high-performance liquid chromatography. Grade 2 water is used for tests like inorganic trace analysis, including atomic absorption spectroscopy. Grade 3 water is suitable for general chemical analysis tests. To ensure water quality compliance, the standard specifies detailed testing methods for key parameters, including conductivity/resistivity, pH value, oxidizable substances, absorbance, evaporation residue, and soluble silica. Conducting these tests requires the use of instruments and equipment such as a conductivity meter (equipped with a conductivity cell of a specific cell constant), a pH meter, a UV-Vis spectrophotometer, and a constant-temperature drying oven.