On August 1st, GB/T 45131-2025 *Analytical Methods for Boiler Water and Cooling Water — Determination of Phosphate, Chloride, Silicate, Total Alkalinity, Phenolphthalein Alkalinity, Hardness and Iron: Spectrophotometric Method Based on Discrete Analyzer Systems* — a new standard for the boiler water quality testing industry — was officially implemented. This standard fills the domestic technical gap in this field. ### Standard Gap: Why Do We Need GB/T 45131-2025? In the field of industrial production, the water quality of boiler water and cooling water directly affects the safe operation of equipment and energy efficiency. Abnormal levels of components such as phosphate, chloride, and silicate in water may cause equipment corrosion, scaling, and even lead to serious accidents. However, for a long time, there has been a lack of standard methods in the domestic boiler water testing field. In particular, the spectrophotometric detection method using discrete analyzer systems has been in a gap state in China. Traditional detection methods have problems such as cumbersome operation, low efficiency, and poor comparability of results among different laboratories. The industry is in urgent need of a standardized, intelligent, and high-efficiency detection solution. The formulation and implementation of GB/T 45131-2025 respond to the requirement of "strengthening the role of standards in the intelligence of inspection and testing" specified in the *National Standardization Development Outline*, and also meet the standard demand for "knowledge and data exchange" in the field of intelligent manufacturing. ### Standard Interpretation: Seven Indicators, One Set of Methods The core content of GB/T 45131-2025 is to standardize the detection methods for seven key indicators in boiler water and cooling water: - Phosphate (calculated as PO₄³⁻): Detection range 1.00 mg/L ~ 50.00 mg/L - Chloride (calculated as Cl⁻): Detection range 10.00 mg/L ~ 100.0 mg/L - Silicate (calculated as Si): Detection range 0.10 mg/L ~ 6.00 mg/L - Total Alkalinity: Detection range 0.50 mmol/L ~ 8.00 mmol/L - Phenolphthalein Alkalinity: Detection range 0.50 mmol/L ~ 5.00 mmol/L - Hardness (calculated as Ca²⁺, Mg²⁺): Detection range 0.50 mmol/L ~ 1.75 mmol/L - Iron Content (calculated as Fe): Detection range 0.10 mg/L ~ 10.00 mg/L This standard is under the jurisdiction of the Water Treatment Chemicals Subcommittee of the National Technical Committee for Standardization of Chemicals, with the competent authority being the China Petroleum and Chemical Industry Federation. The standard document describes in detail the method steps and condition requirements for determining the content of the above indicators using discrete analyzer systems, providing a unified technical specification for the industry.