This standard specifies a method for the determination of tetracaine and its salts in cosmetics by ion chromatograph. It is suitable for the analysis of emulsions, water agents, facial cleansers and facial mask cosmetics. The method includes reagents and materials, instrumentation equipment, test steps and data processing to ensure that the detection limit is 10 mg/kg and the quantification limit is 25 mg/kg. The test samples are purified by solvent ultrasonic extraction, microporous membrane filtrate and solid phase extraction column, separated by ion chromatograph, and determined by Conductivity Detector Detector. Retention time for preliminary qualitative analysis, External standard method for quantitative analysis, designed to accurately detect the content of tetracaine and its salts in cosmetics, in order to comply with the relevant control requirements of prohibited substances.