Abstract:

A method based on ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry（UPLC-Q-TOF-MS） had been developed for the simultaneous determination of monochloroacetic acid, dichloroacetic acid and glycollic acid in cocamidopropyl betaine surfactant. The samples were dissolved by water, then purified by solid phase extraction and separated by a core-shell sub-3 μm column Agilent Poroshell 120 EC-C₁₈（3.0 mm×100 mm×2.7 μm） with a gradient elution of 0.1% formic acid and acetonitrile. Under electrospray ion source negative ion full scan mode, the extracted accurate ion was used to do qualitative and quantitative determination. The results show that the linearity of the three compounds is good in a certain concentration range, and the correlation coefficients are greater than 0.998.The average recovery of the three levels ranges from 71.1% to 92.2%, and the relative standard deviation（RSD） is less than 15%. The detection limits of the optimized method are 0.25 mg/kg for monochloroacetic acid, 0.025 mg/kg for dichloroacetic acid and10 mg/kg for glycollic acid.

Key words: UPLC-Q-TOF-MS, cocamidopropyl betain, monochloroacetic acid, dichloroacetic acid, glycollic acid