Electrochemical sensors based on l-tryptophan molecularly imprinted polypyrrole and polyaniline

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2022-07, Vol.917, p.116389, Article 116389
• Main Authors: Ratautaite, Vilma, Brazys, Ernestas, Ramanaviciene, Almira, Ramanavicius, Arunas
• Format: Article
• Language: English
• Subjects: Chemical sensors; Conducting polymers; Conducting polymers (CP); Electrodes; Imprinted polymers; l-Tryptophan; Molecularly imprinted polymers (MIP); Polyaniline (PANI); Polyanilines; Polymers; Polypyrrole (Ppy); Polypyrroles; Sensors; Tryptophan; Voltammetry
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2022.116389

•Electrochemical sensor based on the molecularly imprinted polymer (MIP) for the detection of l-Tryptophan.•Pyrrole and aniline were used for electrochemical deposition of MIPPpy and MIPPANI layers on the graphite electrode.•MIPPpy and MIPPANI layers were electrochemically deposited on the electrode by potential cycling.•MIP-modified electrodes were evaluated by differential pulse voltammetry (DPV) and cyclic voltammetry.•MIPPpy layer has greatest affinity towards l-Tryptophan molecules in comparison with other evaluated layers. The aim of this work was to compare two different conducting polymers (polypyrrole and polyaniline) in the design of the molecularly imprinted polymer (MIP). An l-tryptophan was selected as a template molecule in such MIP-based layers deposited on the graphite electrodes. Further, the MIPs with l-tryptophan imprints were applied in the design of electrochemical sensors for the detection of l-tryptophan. All polymer layers were electrochemically deposited on the electrode surface by the application of potential cycling. The characteristics of all modified electrodes were evaluated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The results demonstrate that the molecularly imprinted polypyrrole MIPpy layer has a greater affinity toward l-tryptophan molecules in comparison with other layers evaluated in this study. This observation proves that polypyrrole is more suitable for the design of the molecularly imprinted polymer-based sensors for the determination of l-tryptophan than polyaniline. The linear relationship between the current intensity of DPV signal obtained on the molecularly imprinted polypyrrole and the concentration of l-tryptophan was obtained from 50 µM to 100 µM with the limit of detection (LOD) of 16.6 µM and the limit of quantitation (LOQ) of 49.8 µM.