Eco-friendly screen-printed sensor using tapioca-based conductive ink modified with coconut fibers

This study presents a novel eco-friendly water-based conductive ink composed of cassava starch (from tapioca flour) and sorbitol, combined with graphite powder and carbon black, for the fabrication of screen-printed electrodes. The electrochemical detection of uric acid was performed via differential pulse voltammetry, achieving a linear range of 5.0-100 μmol L^-1 and a detection limit of 0.34 μmol L^-1. The disposable sensors exhibited recovery rates ranging from 86.9 % to 112.1 % for synthetic urine and human serum samples. Additionally, a sensor was developed using the same conductive ink, incorporating coconut fiber into the formulation. Cyclic voltammetry was employed to detect hydrogen peroxide, with a linear range from 2.3 to 11.4 mmol L^-1 and a detection limit of 0.6 μmol L^-1. The sensor demonstrated satisfactory performance for pharmaceutical applications, with recovery rates ranging from 90.3 % to 106.9 %. This work highlights the potential of water-based conductive inks using starch as a binder and coconut fiber in the development of sustainable electrochemical sensors, paving the way for environmentally friendly devices in analytical applications.