Determination of Methyl p-Toluenesulfonate and Ethyl p-Toluenesulfonate in Medroxyprogesterone Acetate by LC-MS

OBJECTIVE To establish a method for detecting genotoxin methyl p-toluenesulfonate and ethyl p-toluenesulfonate in medroxyprogesterone acetate by LC-MS.METHODS The determination was peformed on XDB-C₁₈ column (50 mm×4.6 mm, 1.8 μm) with mobile phase A(10 mmol·L^-1 ammonium acetate, adjust pH to 7.0 with aqueous ammonia) and mobile phase B(acetonitrile). The mass spectrometer was performed in SIM m/z:187.1, 201.1 by positive monitoring.RESULTS Both of methyl p-toluenesulfonate and ethyl p-toluenesulfonate were linear in the range of 0.05-5.08 μg·mL^-1. LOQ and LOD of methyl p-toluenesulfonate was 0.10 ng and 0.05 ng, LOQ and LOD of ethyl p-toluenesulfonate was 0.03 ng and 0.02 ng. Their recoveries were 101.6% and 98.7%, with RSDs of 3.46% and 2.22%, respectively.CONCLUSION This method is applicable to the detection of methyl p-toluenesulfonate and ethyl p-toluenesulfonate in medroxyprogesterone acetate.