Characterization of Related Substances in Etimicin Sulfate Sample by High Performance Liquid Chromatography-Electrospray Ionization-Ion Trap-Mass Spectrometry
A high performance liquid chromatography-electrospray ionization-ion trap-mass spectrometry(HPLC-ESI-IT-MSn) method for the identification of related substances in etimicin was established. The analytical conditions were as follows: Phenomnex Gemini NX C18(150 mm×4.6 mm, 5 μm) column; the mobile phase:[water-ammonia-glacial acetic acid(96∶3.6∶0.4)]-methanol(70∶30); flow rate of mobile phase: 1 mL/min; temperature of ESI ion source: 350 ℃; nebulizing pressure: 275.8 kPa; dry gas flow: 10 L/min and the analytes were detected in the positive mode. Eighteen related substances in a etimicin sample were separated and detected by HPLC-ESI-IT-MSn and thirteen related substances were deduced, they are gentamicin C1a, micronomicin and its three isomers, two etimicin′s isomers, two degradation products of etimicin, two homologues of etimicin, and two other unknown compounds, the other five related substances which MS and MS2 data were detected can not be elucidated.