Synthesis of Graphite-Based Conductive Paint for Flexible Paper Electrode for Voltammetric Detection of Lawsone in Cosmetic Product

In this study, a voltammetric technique was adopted for the determination of lawsone concentration using a conductive paint-based flexible paper electrode (CP-FPE). A low-cost conductive paint was formulated that composed of graphite, chloroform, and polyacrylate, serving as the sensing material, solvent, and binder, respectively. The cyclic voltammetry was employed for sensitive detection of lawsone, with a detection potential of -0.1 ± 0.008 V against an Ag/AgCl (saturated KCl) reference electrode in a phosphate buffer solution (PBS) at pH 6.0. The electrode exhibited a linear detection range from 5 to 200 µM, with a detection limit of 0.045 ppm. This proposed electrode offers several advantages, including ease of preparation, miniaturization, disposability, and biodegradability. The successful application of the developed electrode for real sample detection using the standard addition technique, with an average recovery rate of 96.07%, is a strong indication of the method's practical effectiveness.