OBJECTIVE:To determine the related substances in Flucloxacillin sodium for injection.METHODS:LC-MS/MS was used.The determination was performed on Hypersil ODS column with mobile phase of acetonitrile-0.5 mmol/L ammonium acetic(pH=5.0)(30:70)at the flow rate of 1.0 ml/min,and the column temperature was 20 ℃.MS parameter:ESI ion source,positive monitoring,Q1 full scan mode,Q2 scan mode,MRM,scanning scope of 100-1 000 amu.RESULTS:5 related substances were identified in Flucloxacillin sodium for injection,and t...