Development of a QuEChERS-HPLC-FLD Procedure for the Simultaneous Detection of Residues of Florfenicol, Its Metabolite Florfenicol Amine, and Three Fluoroquinolones in Eggs

Abstract

A method utilizing high-performance liquid chromatography-fluorescence detection (HPLC-FLD) has been developed and refined for the simultaneous detection of florfenicol (FF) and its metabolite florfenicol amine (FFA) along with three fluoroquinolone (ciprofloxacin (CIP), enrofloxacin (ENR), and sarafloxacin (SAR)) residues in different parts of eggs (whole egg, egg yolk, and egg albumen). The QuEChERS ("Quick, easy, cheap, effective, rugged, and safe") procedure utilized 0.1 M disodium EDTA solution, water, and acetonitrile as extractants; sodium sulfate, sodium chloride, and trisodium citrate as dehydrating salts; and N-propylethylenediamine and C18 as adsorbents. A dual-channel FLD method was utilized to analyze the target compounds using an XBridge BEH C18 chromatographic column (4.6 mm × 150 mm, 5 μm). The mobile phase was employed isocratically using a solution of 0.01 M sodium dihydrogen phosphate, 0.005 M sodium dodecyl sulfate, and 0.1% triethylamine (pH 4.8) in combination with acetonitrile at a ratio of 65:35 (V/V). The limits of detection (LOD) and quantification (LOQ) of the analytes ranged from 0.03 to 1.5 µg/kg and from 0.1 to 5.0 µg/kg, respectively. The recoveries of the analytes in the blank egg samples ranged from 71.9% to 94.8% when reference standard concentrations of the LOQ, half of the maximum residual limit (MRL), MRL, and twice the MRL were added. The parameters of the presented protocol were validated and subsequently applied to the analysis of real samples, demonstrating the applicability and reliability of the method.

Keywords: HPLC–FLD; QuEChERS; egg; florfenicol; fluoroquinolones.

Figure 1

Chromatograms of mixed standard working solution, blank whole egg, and whole egg fortified with standards. Channel A: (a), mixed standards (FF: 40.0 µg/L, FFA: 20.0 µg/L); (b), blank whole egg; (c), whole egg fortified with standards (FF: 20.0 µg/kg, FFA: 10.0 µg/kg). Channel B: (d), mixed standards (CIP: 20.0 µg/L, ENR: 5.0 µg/L, and SAR: 20.0 µg/L); (e), blank whole egg; (f), whole egg fortified with standards (CIP: 10.0 µg/kg, ENR: 2.5 µg/kg, and SAR: 10.0 µg/kg).

Figure 2

Chromatograms of mixed standard working solution, blank egg yolk, and egg yolk fortified with standards. Channel A: (a), mixed standards (FF: 40.0 µg/L, FFA: 20.0 µg/L); (b), blank egg yolk; (c), egg yolk fortified with standards (FF: 20.0 µg/kg, FFA: 10.0 µg/kg). Channel B: (d), mixed standards (CIP: 20.0 µg/L, ENR: 5.0 µg/L, and SAR: 20.0 µg/L); (e), blank egg yolk; (f), egg yolk fortified with standards (CIP: 10.0 µg/kg, ENR: 2.5 µg/kg, and SAR: 10.0 µg/kg).

Figure 3

Chromatograms of mixed standard working solution, blank egg albumen, and egg albumen fortified with standards. Channel A: (a), mixed standards (FF: 40.0 µg/L, FFA: 20.0 µg/L); (b), blank egg albumen; (c), egg albumen fortified with standards (FF: 20.0 µg/kg, FFA: 10.0 µg/kg). Channel B: (d), mixed standards (CIP: 20.0 µg/L, ENR: 5.0 µg/L, and SAR: 20.0 µg/L); (e), blank egg albumen; (f), egg albumen fortified with standards (CIP: 10.0 µg/kg, ENR: 2.5 µg/kg, and SAR: 10.0 µg/kg).