Water-Based Conductive Ink for the Production of Carbon Black Screen-Printed Electrodes and the Detection of Tryptophan

High Resolution Image Download MS PowerPoint Slide The development of versatile, cost-effective, and reproducible electrochemical sensors has gained importance due to their adaptability to specific applications through variations in composition and design. Water-based conductive inks have emerged as environmentally friendly alternatives to meet sustainability requirements and eliminate hazardous solvents. In this study, a screen-printed electrode (SPE) sensor utilizing a water-based conductive ink composed of Carbon Black Super P (CBSP), poly(vinylpyrrolidone) (PVP) and chitosan is presented. The ink formulation was optimized for a 5% CBSP composition, resulting in a homogeneous surface and superior reproducibility with a relative standard deviation of 7.99% ( n = 5). The optimized sensor exhibited quasi-reversible behavior in cyclic voltammetry and an electroactive area 198.57% larger than its geometric area. The analytical performance for tryptophan detection showed a linear range from 0.5 to 300 μmol L –1 ( R 2 = 0.9946), a limit of detection of 0.018 μmol L –1, and interference rates below 10% for common compounds. The recovery rates for pharmaceutical and beverage samples ranged from 86.2% to 114%. The sustainable design, excellent sensitivity, and cost-effective manufacturing make this SPE sensor a robust tool for point-of-use tryptophan quantification.