An ultrasensitive chemiluminescent ELISA for determination of chloramphenicol in milk, milk powder, honey, eggs and chicken muscle

A competitive, direct, chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for chloramphenicol (CAP) residues in milk, milk powder, honey, eggs and chicken muscle has been developed. The method gave a detection limit of 0.7 ng L⁻¹ and a linear range of 2.1–92.4 ng L⁻¹, with the IC₅₀ of 13.6 ng L⁻¹ under optimal conditions, dramatically better than any previously reported ELISA method for CAP detection. Spiked at levels of 5–60 ng L⁻¹ in different food samples, recoveries were in the range of 72.1–116.0%, with coefficient of variations of 4.2–20.2%. In a study of incurred residues, the chicken muscle samples diluted 5-, 10- and 20-fold, results obtained by CL-ELISA correlated well with those obtained by gas chromatography with microcell electron capture detector and traditional ELISA. The developed CL-ELISA method is, therefore, suitable for rapid screening trace CAP residues in food samples.