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

R Camargo, J ORCID: https://orcid.org/0000-0003-1836-7495, Crapnell, RD ORCID: https://orcid.org/0000-0002-8701-3933, Bernalte, E, Janegitz, BC ORCID: https://orcid.org/0000-0001-9707-9795 and Banks, CE ORCID: https://orcid.org/0000-0002-0756-9764 (2025) Water-Based Conductive Ink for the Production of Carbon Black Screen-Printed Electrodes and the Detection of Tryptophan. ACS Applied Electronic Materials, 7 (12). pp. 5599-5610. ISSN 2637-6113

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Abstract

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 (R2 = 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.