An Electrochemical Sensor for L-Tryptophan Using a Molecularly Imprinted Polymer Film Produced by Copolymerization of o-Phenylenediamine and Hydroquinone

Abstract

An electrochemical sensor for L-tryptophan based on a molecularly imprinted polymer was developed. The sensing film was prepared by the co-electropolymerization of o-phenylenediamine and hydroquinone on a gold electrode in the presence of L-tryptophan as the template. The performance of the L-tryptophan sensor was characterized by cyclic voltammetry, differential pulse voltammetry, and alternating current impedance. Under the optimal experimental conditions, the relative current change was linear to the concentration of L-tryptophan in the range of 1.0 × 10⁻⁸ to 1.0 × 10⁻⁶ mol/L and a detection limit of 0.50 × 10⁻⁸ mol/L was obtained. The sensor showed high sensitivity and selectivity for L-tryptophan. The imprinting factor was 3.58 and selectivity factors of L-tryptophan compared to analogs were larger than 2. The sensor also demonstrated good resistance to acidic, basic, and organic environments.

Keywords:

• Electrochemical sensor
• Electropolymerization
• Hydroquinone
• L-tryptophan
• Molecularly imprinted film
• O-phenylenediamine

Notes

^a Carbon nanofibers-carbon paste electrode.

^b 1-[4 (Ferrocenyl ethynyl) phenyl]-1-ethanone.

^c Multi-walled carbon nanotube.

^d Layered double hydroxide.

^e 4-Aminobenzoic acid-glassy carbon electrode.

^f Silver nanoparticles.

^g Graphene oxide.

^h Boron-doped diamond nanowires.

ⁱ Gold electrode.

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