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

Magnetic Fe 3 O 4 nanoparticles were synthesized by co-precipitation method, and then magnetic Fe 3 O 4 @Au nanoparticle were synthesized to improve the affinity of particle surface. L -Cys-GA3 was grafted on the particle surface by self-assembly method, and then dropped it on glass carbon electrode. The MIP/Fe 3 O 4 @Au was further fabricated by electropolymerization of L -Cys. The surface morphology and particle size distribution of the Fe 3 O 4 @Au particle were studied by TEM. The structure and composition of GA3, MIP and nMIP were studied by IR. Under the optimum conditions including 30 cycles of electropolymerization period, 5 min of elution time, 7 min of rebinding time and with acetic acid-methanol (1:8, V / V ) mixed solution as eluent, high stability and good recognition ability for GA3 were obtained through the sensor. The results showed that the concentration of GA3 in the range of 1.0 × 10 −11 −1.0 × 10 −8 M had a linear relationship with the intensity of the oxidation peak current, with the detection limit of 2.6 × 10 −12 M. The sensor was successfully used for the determination of GA3 in beer sample.