Bridging electrochemical performance and affordability: the challenges in characterizing emergent low-cost...

The transition from laboratory electroanalytical setups to low-cost electrochemical systems has opened the way for new possibilities for point-of-care diagnostics and environmental monitoring in resource-limited contexts. Recent technologies for material processing, such as additive manufacturing, laser cutting/engraving systems, and open-source electronics, have lowered fabrication costs and expanded access to these devices. However, the electrochemical characterization of low-cost sensors poses challenges when using conventional models, which are useful for characterization under appropriate conditions but may compromise data reliability and complicate comparisons of sensor performance across studies for low-cost materials/platforms. In this review, we provide a critical assessment of the limitations in the electrochemical characterization of low-cost electrochemical devices, along with guidance on estimating electroactive surface area, the use of redox probes, the impact of uncompensated resistance, and the validity of calculating frequency-dependent kinetic parameters. Additionally, the reproducibility and long-term stability of these devices are discussed. Through this, we aim to clarify the factors that lead to miscalculations and misinterpretations in the application of the current literature in low-cost devices characterization and to provide best practices for control experiments and calibration/validation requirements. As a result, we expect that this work will support the development of more reliable standards for the characterization, reproducibility, and validation of low-cost electrochemical sensors for real-world applications.