Abstract:

A multi-residue analytical method based on solid-phase extraction (SPE) with multi-walled carbon nanotubes (MWCNTs) as sorbent was developed. The determination of the sulfonamides (SAs) in pork and chicken was carried out by high performance liquid chromatography-ultraviolet detection (HPLC-UV). The clean-up conditions were optimized. The analytes were extracted by acetonitril and cleaned-up by MWCNTs SPE cartridge. The extract was re-dissolved with the Na₂HPO₄ buffer (pH 5.5-6.0) for loading, and was washed with acetone-hexane (5:95, v/v), then eluted with acetone-dichloromethane (1:1, v/v) from the column. The mobile phase used in the chromatographic separation consisted of a binary mixture of acetonitrile and 50 mmol/L NaH₂PO₄ with the volume ratio of 7:3. A wide linear range was 0.01-1.00 mg/L with the correlation coefficients above 0.998. The limits of detection (S/N=3) were 0.003 mg/L, and the limits of quantification (S/N=10) were 0.01 mg/L. The average recoveries were over 70% for the nine SAs in the spiked range of 0.02-0.2 mg/kg, with the relative standard deviations (RSDs) lower than 8%. This study indicated that the MWCNTs SPE cartridge is efficient for the clean-up of the SAs in animal tissues or products, and the method is simple, accurate and suitable for the quantification of the SAs residues.

Key words: chicken, high performance liquid chromatography-ultraviolet detection (HPLC-UV), multi-walled carbon nanotubes (MWCNTs), pork, solid-phase extraction (SPE), sulfonamides (SAs)