GB/T 9724-2007 stipulates general rules for the determination of pH value of chemical reagents. Applicable to all kinds of chemical reagents, covering samples of different properties. The standard details the pretreatment method of the sample, and clarifies the operation process for the determination of pH value using instruments such as acidity meters, including instrument calibrating, electrode selection, measurement environment requirements, etc. It also regulates the recording and processing of measurement results to ensure accurate and reliable measurement results. The standard provides an important basis for the quality control of chemical reagents and is widely used in chemical reagent production, scientific research, analysis and testing and other fields to ensure the accuracy of chemical experiments and production.