ELISA validation and determination of cut-off level for chloramphenicol residues in honey

An analytical validation of a screening ELISA for detection of chloramphenicol (CAP) in honey was conducted according to the Commission Decision 2002/657/EC and Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines. The analyte was extracted from honey with a water and ethyl acetate mixture, and CAP concentrations were measured photometrically at 450 nm. The recovery rate of the analyte from spiked samples was 79%. The cut-off level of CAP in honey as the minimum recovery (0.17 units) was established. Detection capability (CCβ) was fixed at 0.25 μg kg⁻¹. No relevant interferences between matrix effects and structurally related substances including florfenicol and thiamphenicol were observed. The ELISA method should be useful for determination of CAP residues in honey monitoring.