GB/T 5551-2010 is used to determine the total content of calcium and mg ions in surfactant dispersants. The standard introduces the determination principle and clarifies the required equipment and reagents. The whole process from sample collection, processing to specific determination is described in detail, including sample dissolving, interference ion removal and other operations, and the use of appropriate titration or instrumental analysis methods to determine the total amount of calcium and mg ions. By following this standard, the calcium and mg ion content in dispersants can be accurately obtained, providing key data for evaluating dispersant performance and controlling product mass, and promoting the standardization and standardization of surfactant industry testing.