Determination of nitrofuran metabolites in sausage casings and crawfish using LC-Q-Orbitrap HRMS: Method development...

This study developed and validated an analytical method for determining four nitrofuran (NF) metabolites in sausage casings and crawfish matrices. The method utilizes liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry (LC-Q-Orbitrap HRMS) to analyze these metabolites. The validation of the developed method was carried out in accordance with the Commission Implementing Regulation (CIR) EU 2021/808, using three concentration levels ranging from 0.25 to 0.75 μg/kg. The recoveries ranged from 77 % to 109 %, while both repeatability and reproducibility remained consistently below 15 %. The calibration curves exhibited good linearity, with correlation coefficients (R) exceeding 0.9978. The limits of detection (LOD) ranged from 0.0218 to 0.0596 μg/kg, while the limits of quantification (LOQ) ranged from 0.0719 to 0.1966 μg/kg. The decision limit (CCα) and detection capability (CCβ) values ranged from 0.30 to 0.39 μg/kg and 0.29-0.35 μg/kg, respectively. Out of 30 crawfish samples collected from local markets in Egypt, 16.66 % contained NF metabolites residues, whereas sausage casings showed no NF metabolite residues. The reliability of the method was further demonstrated through successful participation in two proficiency testing (PT) rounds.