Quantitative Analysis of Decoquinate by Derivatization-Gas Chromatography Tandem Mass Spectrometry in Egg Samples

Abstract

A novel precolumn derivatization-gas chromatography-tandem mass spectrometry (GC-MS/MS) method for the confirmation and detection of decoquinate residues in eggs (whole egg, albumen, and yolk) was developed. Liquid-liquid extraction (LLE) was used for sample extraction and separation, and solid phase extraction (SPE) was used for sample purification. Pyridine and acetic anhydride were used for the derivatization reaction, and the derivatives were injected into the GC-MS/MS for detection. After the experimental conditions were optimized, satisfactory sensitivity was obtained. The limits of detection (LODs) and limits of quantification (LOQs) of decoquinate in eggs (whole egg, albumen and yolk) were 1.4~2.4 μg/kg and 2.1~4.9 μg/kg, respectively. At four spiked concentration levels, the average recoveries were 74.31%-89.77%, the intraday relative standard deviations (RSDs) ranged from 1.22% to 4.78%, and the interday RSDs ranged from 1.61% to 7.54%. In the concentration range of the LOQ~250 μg/kg, the linear relationship was excellent with all correlation coefficients (R2) greater than 0.9990. The method has excellent linearity, and the parameters meet the European Union veterinary drug residue testing requirements. The feasibility and practicality of the method were confirmed by sample testing of eggs from a local supermarket. Therefore, this study established an LLE-SPE-GC-MS/MS for the analysis of decoquinate residues in eggs.

Keywords: Egg, Decoquinate, Precolumn derivatization, LLE-SPE, GC-MS/MS