APPLICATION OF POLARIZATION FLUORESCENCE IMMUNOASSAY FOR THE DETERMINATION OF FLUNIXIN IN MILK

The technique of polarization fluorescence immunoassay for the detection of residual amounts of nonsteroidal anti-inflammatory drug flunixin used for prophylaxis and treatment in veterinary medicine and animal husbandry was developed. The optimal analysis time was 15 min taking into account sample preparation, the linear range was 20-5000 ng/mL, and the limit of detection was 2 ng/mL. High selectivity of immunoreagents with respect to the antigen under study was shown; cross-reactivity coefficients with preparations having structural similarity to flunixin did not exceed 0.01 %. The method of flunixin determination in milk was tested by the injected-found method, it was shown that the application of the developed method of sample preparation allows effective detection of the investigated antigen within the linear range. These results indicate the possibility of using the developed technique with the use of polyclonal antibodies for express and sensitive determination of flunixin in milk.