Competitive ELISA of chloramphenicol: Influence of immunoreagent structure and application of the method for the inspection of food of animal origin

An indirect competitive ELISA for the detection of chloramphenicol (CAP) in food of animal origin (milk, meat, eggs) is described. Influence of immunoreagent structure and composition on the assay sensitivity and specificity was investigated. Two CAP derivatives were used for conjugation with proteins: CAP succinate and a diazo derivative of CAP. Molar incorporation of CAP into the coating conjugates was also varied. To eliminate matrix effect on the assay results, a special casein-containing buffer was used for milk samples, whereas for meat and egg samples a 50-fold dilution of the buffer extracts was needed. The method developed permits CAP concentrations to be determined in the range 0.08-100 mu g l(-1). The detection limit is 0.08 mu g kg(-1). Recovery in different food samples averages between 70 and 130%. The method can be applied for inspection of food of animal origin for CAP residues.