Analysis of tetracycline residues in royal jelly by liquid chromatography–tandem mass spectrometry

A confirmatory method coupling liquid chromatography with tandem mass spectrometry (LC/MS/MS) was developed to determine the concentration of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC) and doxycycline (DC), which make up the tetracycline (TC) groups present in royal jelly. Sample preparation included deproteination, control of pH, extraction and clean-up on a solid-phase extraction (SPE) cartridge. The analyses were achieved by LC/MS/MS in selected reaction monitoring mode (SRM). The overall recovery of fortified royal jelly at the levels of 5.0, 10.0 and 40.0 μg/kg ranged from 62% to 115%, and the coefficients of variation ranged from 3.4% to 16.3% (n = 6). The detection limits for TCs were under 1.0 μg/kg. The transformation between the TCs and its epimers (EpiTCs) was studied in standard solution and during the sample preparation process. This method can be used for the detection of tetracycline residues in royal jelly.