Plataformas Eletroanalíticas Baseadas em Impressão 3D: Abordagens Sustentáveis e de Baixo Custo para Análises Farmacêuticas, Ambientais e Forenses

Abstract

This thesis presents the development of three alternative electrochemical systems for analytical applications. The work is divided into four chapters: Chapter 1 outlines the essential theoretical concepts necessary to understand the conducted studies; Chapter 2 introduces an innovative electrochemical sensor made with pencil-drawn electrodes (PDE) and a biodegradable substrate 3D-printed via masked stereolithography (MSLA). This low-cost (~R$ 0.60) device has a reduced environmental impact. Compared to paper, the MSLA 3D substrate is hydrophobic and more resistant, ensuring more stable and durable sensors. Additionally, the MSLA-3D-PDE, combined with a custom-designed cell, demonstrated great electrochemical performance, similar to that of a glassy carbon electrode, without requiring activation. The platform was applied to omeprazole quantification, achieving a detection limit of 0.72 μmol L⁻¹ with high precision (error ≤ 1.50%). Its sustainability was confirmed using the Eco-Scale index, highlighting the MSLA-3D-PDE as a promising tool in electroanalysis; Chapter 3 presents a new approach for sample injection in microfluidic thread-based electroanalytical devices (μTED), replacing manual micropipettes with electronic pipettes for improved precision and reproducibility. A novel 3D-printed platform was developed to attach the electronic pipette to the μTED, ensuring injections occur in a fixed position, thereby enhancing measurement reproducibility. To demonstrate practical applicability, this approach was used to analyze Fe²⁺ ions in pharmaceutical supplements and environmental samples. The method exhibited a wide linear range (0.70 to 200.0 μmol L⁻¹), a low detection limit (0.21 μmol L⁻¹), high accuracy (recoveries between 96% and 103%), and excellent precision (relative standard deviation ≤ 3.3%). Thus, automated injection represents a significant advancement in the state of the art for μTEDs; Chapter 4 investigates the electrochemical characterization and forensic application of ADB-butinaca (ADB-B), a synthetic cannabinoid increasingly seized in Brazil. Using conventional electrodes and a 3D-printed cell, a portable and cost-effective method was developed. Studies demonstrated the method’s high precision and accuracy (107-108% recovery) and enabled the selective detection of ADB-B in seized samples, achieving over 80% accuracy in a quantification blind test. The results highlight the potential of this methodology for rapid forensic identification of ADB-B in the field, aiding in drug trafficking control.