Disposable and low-cost lab-made screen-printed electrodes for voltammetric determination of L-dopa

Abstract

This work presents a feasible process for preparation screen-printed electrode (SPE) using a lab-made conductive ink based on cellulose acetate (CAc) and graphite powder (GP) printed on polyvinyl chloride (PVC) sheet. The CAc present in the composition of this SPE is a binding agent for conductive inks with GP, which are relatively low-cost and easily obtainable materials, compared to other similar commercial sensors. The SPE was evaluated through cyclic voltammetry (CV) using an equimolar [Fe(CN)6]3-/4− solution as a redox probe to find an adequate ink composition. Electrode surface was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). To show the analytical potential of SPE proposed it was used for Levodopa (L-dopa) determination. L-dopa is a drug frequently used to reduce the symptoms of Parkinson's disease. The GP-CAc/PVC electrode was evaluated for the determination of L-dopa under square wave voltammetric (SWV) conditions. The electrode presented a linear dynamic range (LDR) from 8.00 to 100 µmol L−1 and a limit of detection (LOD) of 0.06 µmol L−1. As a proof-of-concept, the proposed electrode was used to quantify L-dopa in drug samples as an alternative tool for quality control tests, being applied to two commercial drugs. The electrode construction strategy proved to be reproducible with an analytical performance comparable to other similar electrodes reported in the literature.