Abstract: A method for the determination of mupirocin in different ointments by the high performance liquid chromatography-mass spectrometry (HPLC-MS) was established. The analytical column was Agilent XDB-C18(2.1 mm × 50 mm，1.8 μm), the mobile phase was 0.1% formic acid solution and acetonitrile with gradient elution, and the flow rate was 0.3 mL·min^-1. The column temperature was set at 30 ℃. The detection was achieved in ESI positive ion mode with 501.3→326.7, 501.3→308.9 and 501.3→291.0. Results showed that the calibration curve was in a linearity over the range of 10～500 ng·mL^-1(r＝0 .999 5). The limit of detection and quantification was 4 ng·mL^-1and 10 ng·mL^-1, respectively. Precision was fine, with RSD（n=6）of 0.8％. The recoveries（n=3）of low, middle and high adding concentrations were 99.8%, 109.2% and 105.0%,and the RSD（n＝3） were 3.5%, 1.6% and 1.4%, respectively. The established method is sensitive, specific, accurate, simple and rapid, which is applicable for the determination of mupirocin in different ointments．

Key words: mupirocin, HPLC-MS, sensitivity, specialization