Authors: C. March, J.J. Manclús, A. Arnau, Y. Jiménez, T. Sogorb, A. Montoya
Event: IBERSENSORS 2006. Montevideo, Uruguay (2006)
A Monoclonal Antibody-based Piezoelectric Immunosensor for the analysis of pesticides was developed. Functionalized AT-cut 9 MHz quartz crystals integrated in a flow-through system were used as the transducer element. Pesticide detection was accomplished by competitive immunoassay in the conjugate-coated format, using specific monoclonal antibodies. Working in the microgravimetric mode, the frequency variations of the piezoelectric crystal were measured and correlated with the concentration of the pesticide in the sample. Frequency signals were inversely proportional to the pesticide concentrations, thus providing decreasing sigmoidal calibration curves. The immunosensor sensitivity (estimated as the assay I50 value) was around 30 µg/l. The limits of detection ( I90 values) were around 7 µg/l. A complete assay cycle, including regeneration, was performed in 20 min. and each sensor could be reliably reused for one hundred times. These analytical performance would allow the detection of pesticides in fruits and vegetables at European regulatory levels.