Determination of Amoxicillin Residues in Eggs by HPLC with Fluorescence Detection

An analytical method for the determination of moxicillin(AMO) residues in eggs was established using HPLC with fluorescence detection.AMO residues in egg samples were extracted with acetonitrile,and the acetonitrile extract was further extracted with saturated methylene chloride and derivatized with salicylaldehyde under acidic conditions in boiling water.The mobile phase used for the chromatographic separation of the derivative was composed of 0.01 mol/L potassium dihydrogen phosphate(A) and acetonitrile(B) at a flow rate of 1.0 mL/min.Fluorescence detection was completed at excitation and emission wavelengths of 354 nm and 445 nm,respectively.The HPLC method showed good linear relationship over the concentration range of 5.0–800 ng/mL(r = 0.9991).The average recoveries of AMO at spike concentrations between 5 ng/g and 125 ng/g were 80.47%–89.53% with a relative standard deviation(RSD) of 5.77%–6.87% and the intra-day and inter-day RSDs were 8.61%–9.61% and 11.01%–14.80%,respectively.The limit of detection and limit of quantification for AMO were 1.2 ng/g(RSN = 3) and 3.9 ng/g(RSN = 10),respectively(n = 6).This method was simple,fast,sensitive and suitable for the determination of AMO in eggs.