This standard GB/T 10267.1-1988 specifies a method for the determination of chlorine content in metallic calcium using a chloride ion selective electrode. This method is suitable for metallic calcium samples with a chlorine content in the range of 300 to 5000 µg/R, and can effectively avoid the interference of impurity elements such as chromium, iron, aluminum, nickel, manganese, silicon, copper, mg, etc. Methods By converting the sample into nitrate after hydrolysis, using sodium nitrate solution as ionic strength agent, under the condition of pH 2 to 7, chlorine determination is carried out directly with a chloride ion selective electrode. The reagents required for analysis and their configuration methods are also listed in detail in the standard to ensure the accuracy and Reliability of the test.