Comparison of various liquid chromatographic methods for the analysis of avermectin residues in citrus fruits

Various liquid chromatographic (LC) techniques for analyzing avermectin (Abamectin) were compared after extraction of residues from citrus fruit samples by matrix solid-phase dispersion (MSPD). LC with UV and fluorescence detection were used as also was LC coupled to the mass spectrometer by an electrospray interface. The results obtained by the three methods were compared in terms of sensitivity and selectivity. The combination of MSPD extraction and LC with fluorescence detection have made it possible to quantify 0.5 microg kg(-1) of Abamectin in 0.5 g of orange sample, with an overall average recovery of 94%. The procedure provides a simple and sensitive method for monitoring Abamectin residues in citrus fruit at the levels required by legislation.