Carbon cloth electrode integrated into a custom 3D-printed architecture for electroanalytical sensing of caffeine

Routine electrochemical analysis can benefit from customizable cells that accommodate non-planar working-electrode materials. Herein, we report on the development of a highly adaptable electroanalytical platform using a carbon cloth (CC) working electrode integrated into a custom 3D-printed cell. The electrochemical properties of the sensor were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy using a [Fe(CN)₆]^3-/4- redox probe solution, while operational stability and sensor-to-sensor reproducibility were assessed via chronoamperometry. The integrated CC platform was subsequently applied for the direct quantification of caffeine (CAF) as a model analyte, by square wave voltammetry (SWV) in commercial energy drink formulations, with performance benchmarked against standard method using a paired Student's t-test at a 95% confidence level. Chronoamperometric evaluations of stability and reproducibility using redox probe yielded excellent RSD below 4.2%, confirming robust fabrication and long-term operational reliability to the electrochemical system. Under optimized SWV conditions, the sensor exhibited a wide linear response from 10 to 2000 μmol L^-1 and a limit of detection of 3.38 μmol L^-1 for CAF. Furthermore, CAF determination by SWV technique demonstrated statistically equivalent analytical accuracy (t_cal < t_crit) compared to the reference UV-vis method across all real samples. Overall, the results demonstrate the CC electrode mounted in a custom rigid 3D-printed architecture offers a reliable alternative for decentralized electrochemical sensing applications.