Determination of amoxicillin in honey by high performance liquid chromatography-tandem mass spectrometry

A method for the determination of amoxicillin in honey by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established. The samples were dissolved by phosphate buffer and cleaned-up by solid phase extraction (SPE) cartridge. The analytes were determined by HPLC-MS/MS on a C18 column with methanol and 0.1% (v/v) formic acid solution as mobile phases with gradient elution. The analysis of amoxicillin was performed under selected reaction monitoring mode by selecting one parent ion and two daughter ions as qualitative ions and the most abundant daughter ion as quantitative ion. The external standard was used for quantitative analysis in this method. The calibration curve showed good linearity in the range of 2.0-100.0 microg/L with good precision and accuracy (r2 > 0.99). The limit of detection (LOD) and limit of quantitation (LOQ) were 2.0 microg/kg and 5.0 microg/kg, respectively. The average recoveries of amoxicillin in spiked honey ranged from 74.2% to 81.7% with the intra-day precisions (relative standard deviations, RSDs) from 2.8% to 7.8% and the inter-day precisions (RSDs) from 9.1% to 11.3%. This method is convenient and suitable for the determination of amoxicillin in honey.