Simultaneous electrochemical determination of dopamine and paracetamol based on thin pyrolytic carbon films

This paper describes the determination of dopamine and paracetamol using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The selective, stable and reproducible simultaneous measurement of the two compounds is achieved using thin pyrolytic carbon (PyC) films as working electrodes. These are created via a reliable, non-catalytic chemical vapour deposition (CVD) process, and the electron transfer characteristics of the films are optimised using a simple oxygen plasma treatment. This new class of carbon electrode can detect dopamine in the range 18 to 270 mu M, with a 2.3 mu M limit of detection (LoD), while simultaneously sensing paracetamol in the range 15 to 225 mM (LoD 1.4 mu M). A 225 mV separation between the two competing signals is realised. The accuracy of the sensor is demonstrated using human serum and commercially available pharmaceutical products. This is the first report of the application of PyC to this problem, and the performance is shown to be competitive with the leading carbon electrodes available today, particularly edge-plane pyrolytic graphite (EPPG). This work will serve as an important benchmark in the development of inexpensive, disposable, high-performance nano-structured electrodes for sensors, fuel cells and energy conversion.