Abstract:

An amperometric immunosensor was fabricated by co-immobilizing penicillin G polyclonal antibody (Ab*)
on the surface of a gold nanoparticle modified glassy carbon electrode through electrostatic adsorption. A highly sensitive
one-step direct electrochemical immunoassay was established due to the strong adsorption and conductive capacity of gold
nanoparticles, thus raising the amount of fixed penicillin G antibody and electrochemical sensitivity. Under optimized
conditions, the current response of the sensor showed a good linear relationship with logarithmic penicillin concentration in
the range of 0.04-40.00 ng/mL with a correlation coefficient of 0.988 4 and the detection limit was 2.49 ng/mL. The method
was able to detect penicillin in milk successfully.

Key words: gold nanoparticles, penicillin, electrochemical immunesensors