A flexible CVD graphene platform electrode modified with l-aspartic acid for the simultaneous determination of acetaminophen, epinephrine and tyrosine

Abstract

A graphene platform electrode (GPE) was fabricated by transferring chemical vapor deposition (CVD) graphene films from copper foils to flexible polyethylene terephthalate substrates supported by polymethyl-methacrylate. l-Aspartic acid (l-Asp) was immobilized onto the surface of GPE by electrodeposition to form a poly-l-Asp/GPE, which was characterized by scanning electron microscopy, energy dispersive spectroscopy and Raman spectroscopy. Hence, a novel poly-l-Asp modified GPE was created for the simultaneous electrochemical determination of acetaminophen (AC), epinephrine (EP) and tyrosine (TY). Cyclic voltammetry was used for investigating the electrocatalytic activity of the poly-l-Asp/GPE sensor towards the detection of AC, EP and TY in comparison with that of GPE. The simultaneous determination of AC, EP and TY was realized by the differential pulse voltammetry technique at poly-l-Asp/GPE. The broad linear ranges to AC, EP and TY were obtained by chronoamperometry, which were from 0.05 to 108.25 μM for AC, 0.025 to 123.3 μM for EP and 0.1 to 93.9 μM for TY, with detection limits (S/N = 3) of 0.011 μM, 0.006 μM and 0.31 μM, respectively. Furthermore, the as-fabricated sensor showed extraordinary stability as well as high anti-interference ability, and was utilized successfully in detecting real samples.