Document - FAVV

Evaluation of immunoassay kits for ochratoxin A determination in cerealstracer. In this case the tracer competes with mycotoxin (from the sample) for a limited amount of mycotoxin-specificantibody. In the absence of mycotoxin the antibody binds the tracer, restricting its motion and causing a highpolarization. In the presence of mycotoxin less of the tracer is bound to the antibody and a greater fraction existsunbound in solution, where it has a lower polarization. With this format the polarization is inversely related to themycotoxin concentration. The polarization fluorescence can be measured at equilibrium, even though it can also bemeasured during the reaction by monitoring the tracer-antibody system (kinetic FPIA, used by Aokin), in the latter apolarization-time kinetic curve is constructed. Kinetic FPIA offers several advantages: (a) by lowering the LOD andLOQ (b) raising the repeatability band reproducibility (c) reducing the dependence on the background signal (whichdoes not change with time due to the dynamic character of the kinetic parameter increasing the accuracy (d) longincubation times are not necessary 61 .61 Perez et al., Journal of pharmaceutical and biomedical analysis, 14, (1996), 917-930CODA-CERVA | Foreword & scope & background 1-7