Preparation of Molecularly Imprinted Electrochemical L-Phenylalanine Sensor with p-Toluene Sulfonic Acid Modified Pt Electrode

Abstract

L-Phenylalanine (L-Phe) sensors were prepared with two steps by modifying the Pt electrode using the molecular imprinting technique. In first step, polymeric films based on p-toluene sulfonic acid (PTSA) were electropolymerized on the Pt electrode in the presence of L-Phe as template molecule. In the second step, L-Phe, the template molecule, was desorbed from the film structure coated on the electrode surface using acid. The surface properties and morphologies of the prepared modified electrodes were checked by SEM analysis technique. These modified electrodes were used for determination of L-Phe by differential pulse voltammetry (DPV). Electrodes obtained by molecular imprinting method showed R2 = 0.9997 in the concentration range of 2–2000 μM L-Phe. The limit of detection (LOD) of L-Phe selective electrodes was found as 0.59 μM and the limit of quantification (LOQ) was 1.77 μM. The first three repetition result with the same modified electrode was observed as 96.83% and the RSD value was 14.96% for ten replicates. For twenty modified electrodes, reproducibility was obtained as 97.67% stable between first electrode and twentieth electrode, and the RSD value was observed to be 2.33%. According to these results, prepared molecular imprinted electrodes have high repeatability, stability and selectivity for the determination of L-Phe.

A Review of Sensors and Biosensors Modified with Conducting Polymers and Molecularly Imprinted Polymers Used in Electrochemical Detection of Amino Acids: Phenylalanine, Tyrosine, and Tryptophan

“…Other researchers developed sensors to detect L-Phe through the molecular imprinting technique. Along these lines, Funda Alışık et al obtained, for the 20 sensors prepared, a stable reproducibility percentage of 97.67%, with an RSD value of 2.33%, thus demonstrating that the sensor prepared from p-toluene sulphonic acid (PTSA) polymeric films had high stability, repeatability, and selectivity for L-Phe [134]. Nihal Ermiş et al used the Thiophen-3-carbonyl tryptophan (TP3C-Trp) monomer, developing electrochemical sensors characterized through CV, drawing a parallel between non-imprinted sensors (NIP) and imprinted ones (MIP) to selectively and sensitively determine L-Phe.…”

“…The novelty of the research is represented by the polyurethane polymer, which gives the sensor good adhesion and a selective permeability. [134].…”

High Sensitive Voltammetric Gentamicin Sensor using Poly (3‐thiophenecarboxylic acid‐co‐3‐methylthiophene) Modified Glassy Carbon Electrode

“…Therefore, there is a need for fast, sensitive, cheap and easy-to-apply determination methods that can easily determine the residual antibiotic level. In this context, electrochemical measure-ment methods attract attention as fast, sensitive and lowcost methods [29][30][31][32][33]. Electroanalytical methods are particularly effective because of their simple application, excellent sensitivity, cost-effectiveness, easy pretreatment procedure, and short review time for tracking bioelectroactive molecules and prescription drugs.…”