Electrochemical sensor based on molecularly imprinted polymer/reduced graphene oxide composite for simultaneous determination of uric acid and tyrosine

This work reported a molecularly imprinted polymer (MIP)/reduced graphene oxide (RGO) composite for simultaneous determination of uric acid and tyrosine. The MIP layer was electropolymerized on the RGO modified electrode using a novel monomer of 2-amino-5-mercapto-1, 3, 4-thiadiazole and the dual template of uric acid and tyrosine. The integration of MIP with RGO resulted in the regular nanostructure and large surface area of the sensing interface. The sensing mechanism of the sensor can be explained by first recognizing the target molecules and then catalyzing the oxidation reactions on the MIP/RGO composite. The electrochemical behavior of uric acid and tyrosine on the MIP/RGO composite was evaluated. Influencing factors, including the electropolymerization scanning cycles, monomer/template ratio, and pH values were optimized. Under the optimal condition, the sensor exhibits wide linear ranges for uric acid (0.01 μM–100 μM) and tyrosine (0.1 μM–400 μM) with detection limits of 0.0032 μM and 0.046 μM, respectively. In addition, this MIP/RGO composite was applied to detect uric acid and tyrosine in serum and urine samples.