Determination of Trace Gibberellin A3 by Magnetic Self-assembly Molecularly Imprinted Electrochemical Sensor

The magnetic Fe sub(3)O sub(4) nanoparticles were synthesized by co-precipitation method, and then magnetic Fe sub(3)O sub(4) Au nanoparticle was synthesized to improve the affinity of particle surface. L-Cys-GA3 was grafted on the surface of gold clad by self-assembly method, and then dropped it on glassy carbon electrode, for further manufacture of MIP/Fe sub(3)O sub(4) Au by using electropolymerzation L-Cys. The surface morphology and particle size distribution of Fe sub(3)O sub(4) Au were studied by TEM. The structure and composition of gibberellins A3, MIP and nMIP were studied by IR. The test system was optimized, and the results showed that when the cycles of electropolymerization was 30, acetic acid; methanol (1:8, V/V) was chosen as eluent, elution time was optimized for 5 min and rebinding time for 7 min, the sensor got a high stability and good recognition ability for gibberellins A3. The concentration of gibberellins A3 in the range of 1.0x10 super(-11) -1.0x10 super(-8) mol/L had a relationship with the oxidation peak current of probe, with the detection limit of 2.57x10 super(-12) mol/L. The sensor was successfully used for the determination of GA3 in beer sample.