Development of a flexible and disposable electrochemical sensor based on poly (butylene adipate-co-terephthalate) and graphite for hydroquinone sensing

Abstract

We propose the manufacture and optimization of a flexible electrochemical sensor composed of graphite and the polymer poly (butylene adipate-co-terephthalate) (PBAT). The characterization was performed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), contact angle, Raman spectroscopy, mechanical tensile tests, and scanning electron microscopy (SEM). The electrochemical composite material shows a high electroactive area (0.52 cm²), with an electron transfer rate constant (k0) of 4.55 × 10−3 cm s−1 for potassium ferricyanide and good reproducibility (relative standard deviation (RSD) of 4.5%). As proof of potentiality, the composite sensor was applied for hydroquinone (HQ) detection using the Differential Pulse Voltammetry (DPV) technique. Under optimized manufacturing and instrumental parameters, a linear concentration ranging from 0.1 to 1.4 mmol L−1 HQ with a LOD of 1.01 × 10−6 mol L−1 and LOQ 3.4 × 10−6 mol L−1 were obtained using the flexible composite sensor. In addition, the proposed method was applied to the detection of HQ in the pharmaceutical ointment sample with good agreement between the labelled value and found by the proposed method. Besides, recovery values ranging from 91.85 to 101.37% were obtained, highlighting the adequate accuracy of the method. The sensors described here have the advantage of being flexible, disposable, reproducible (RSD = 4.5%), and of low manufacturing cost ($0.17 per device), which makes them attractive for portable analysis.