SGMS Meeting 2001

Challenges in Food Trace Analysis by LC-MS/MS: Sulfonamides in Honey

L.Verzegnassi
Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, P.O. Box 44, 1000 Lausanne 26.

Residues of antibiotics such as sulfonamides can be found in honey due to their prophylactic and often illegal use to combat diseases in bees. These residues are of great concern because of the potential allergenic reactions they may illicit in certain individuals and their potential contribution to the increase of antibiotic resistance via the food chain.

Trace analyses of antimicrobials in complex matrices such as food require detection methods that can achieve part-per-billion (ppb) levels. Liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is indeed the technique of choice, yielding conclusive evidence on the analyte identity at such low concentrations.

However, simultaneous quantitation of multiple sulfonamides in honey extracts by LC-ESI-MS/MS becomes challenging because of the considerable matrix effect. The impact of the honey matrix on the ionization efficiency varies from one honey to other, making matrix-matched quantitation without an internal standard for each analyte difficult. Thus, the use of a 13C6 sulfonamide standard in such a selective multiresidue method does not allow to compensate for matrix effects and can only be used to assess the ruggedness of the technique.