Electropolymerized molecular imprinting on glassy carbon electrode for voltammetric detection of dopamine in biological samples

• An easy-to-make and low-cost MIP sensor was constructed.
• Molecularly imprinted polyethacridine (PET) with dopamine (DA) was the molecular recognition element of amperometric sensor.
• PET-DA film was electrodeposited on pretreated GCE.
• The MIP sensor exhibited high sensitivity and selectivity towards DA.
• The obtained detection limit for dopamine was 4.4 nM by using DPV.

A simple and reliable method for preparing a selective dopamine (DA) sensor based on a molecularly imprinted polymer of ethacridine was proposed. The molecularly imprinted polymer electrode was prepared through electrodepositing polyethacridine-dopamine film on the glassy carbon electrode and then removing DA from the film via chemical induced elution. The molecular imprinted sensor was tested by cyclic voltammetry as well as by differential pulse voltammetry (DPV) to verify the changes in oxidative currents of DA. In optimized DPV conditions the oxidation peak current was well-proportional to the concentration of DA in the range from 2.0×10−8 M up to 1×10−6 M. The limit of detection (3σ) of DA was found to be as low as 4.4 nM, by the proposed sensor that could be considered a sensitive marker of DA depletion in Parkinson's disease. Good reproducibility with relative standard deviation of 1.4% and long term stability within two weeks were also observed. The modified sensor was validated for the analysis of DA in deproteinized human serum samples using differential pulse voltammetric technique.

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