Submitted to: Journal of Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2007
Publication Date: 2/8/2008
Citation: Lopez, M., Pettis, J.S., Smith Jr., I.B., Pak-Sin, C. 2008. Multi-class determination and confirmation of antibiotic residues in honey using LC-MS/MS. Journal of Food Chemistry. 56(5):1553-1559. Interpretive Summary: Honey is a natural product produced by honey bees that the consumer views as pure. This pure reputation can be threatened if residues of foreign substances are allowed to reach the consumer. Food safety is a real issue in honey as recently honey from China was banned due to detection of antibiotics. This research documents the development of an efficient new screening method to detect antibiotic residues in honey. This information will be useful in screening honey for unwanted contaminates prior to honey reaching the consumer. This information will be used by regulatory agencies such as FDA and by private honey packing companies.
Technical Abstract: A multi-class method was developed for the determination and confirmation in honey of tetracyclines (chlortetracycline, doxycycline, oxytetracycline, and tetracycline), fluoroquinolones (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, and sarafloxacin), macrolides (tylosin), lincosamides (lincomycin), aminoglycosides (streptomycin), sulfonamides (sulfathiazole), phenicols (chloramphenicol) and fumagillin residues using liquid chromatography tandem mass spectrometry (LC-MS/MS). Due to low recoveries, erythromycin (a macrolide) and monensin (an ionophore) can be detected and confirmed but not quantitated. Honey samples (~ 2g) are dissolved in 10 mL of water and centrifuged. An aliquot of the supernatant is injected in the LC-MS/MS to determine streptomycin. The remaining supernatant is filtered through a fine-mesh nylon fabric and cleaned up by solid phase extraction. After solvent evaporation and sample reconstitution, fifteen antibiotics are assayed by LC-MS/MS using ESI in positive mode. Afterwards, chloramphenicol is assayed using ESI in negative mode. The method was validated at the low part per billion levels for most of the drugs with accuracies between 65 – 104% and coefficients of variation (CV) of = 16%. The evaluation of matrix effects caused by honey of different floral origin is presented.