Determination of sarafloxacin residues in fortified and incurred eggs using on-line microdialysis and HPLC/programmable fluorescence detection

Isolation of sarafloxacin (SAR) from fortified and incurred chicken eggs was done by a combination of liquid-liquid extraction and aqueous on-line microdialysis performed on an automated trace enrichment of dialysates (ASTED) system. The ASTED system coupled a sample cleanup procedure with HPLC and programmable fluorescence detection. Overall recoveries of 87-102% for SAR were obtained from samples fortified over a range of 1-100 ng/g. The relative standard deviation values ranged from 22 to 26% for samples fortified between 1 and 5 ng/g and from 2 to 12% for samples fortified between 10 and 100 ng/g. The limits of detection and quantitation were 0.2 and 1 ng/g, respectively. Eggs containing incurred SAR, which were collected over a 3-day dosing period and for 5 consecutive days thereafter, also were analyzed by using this technique. Because the method is automated, 35 samples can be processed within a 24-h period, which enables large data sets to be acquired over a short time period.