Abstract: A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of 13 antibiotics in oral hygiene products, including five tetracyclines, three macrolides, two quinolones, one β-lactam and two lincosamides. The sample was extracted with 0.1% (volume percentage, same hereinafter) formic acid-acetonitrile (95:5, v/v), then centrifuged, filtered and diluted. The target compounds were separated on a C18 column (150 mm×2.1 mm, 5 μm) with a gradient elution of 0.1% formic acid and acetonitrile as the mobile phases, and detected by tandem mass spectrometry in positive electrospray ionization and multiple reaction monitoring (MRM) mode. The quantification of 13 antibiotics was performed by the external standard method. The calibration curves showed good linearity in the range of 5.0~50.0 μg/L with detection limits of 10.0 mg/kg. The recoveries of antibiotics in mouthwash and toothpaste samples at the three spiked levels of 10, 20 and 100 mg/kg were in the range of 80.1%~115% with the relative standard deviations in the range of 0.94%~8.69%. This method is accurate, reliable, simple, and suitable for the analysis of antibiotics in oral hygiene products.

Key words: antibiotics, oral hygiene products, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)