Impressão 3D aplicada à eletroanálise: manufatura de célula eletroquímica, filamento condutor e aplicação no meio ambiente.

Abstract

In this work, we first present a novel disposable electrochemical cell designed for the analysis of small volumes (50 to 2000 µL). The cell consists of only two fully 3D-printed components, allowing for easy integration of various materials as the working, reference, and auxiliary electrodes. As a proof of concept, paracetamol, cocaine, and uric acid were used as model analytes, with different materials employed as the working electrode. Linear calibration curves (R2 > 0.99) with similar slopes (0.29 ± 0.01 μA μmol L⁻¹; RSD = 3.4%) were obtained using square wave voltammetry for different volumes of paracetamol standard solutions (50, 100, and 200 μL). For uric acid, a linear range of 10–125 μmol L⁻¹ (R2 > 0.99) was achieved using differential pulse voltammetry and a laser-induced graphene-based electrode as the working electrode. When a boron-doped diamond working electrode was used, successful screening tests were conducted on cocaine samples, enabling selective detection of cocaine in the presence of common adulterants, with a recovery rate of 103 ± 4%. In the second part of the study, we proposed the development of a filament with a high conductive load while maintaining good printability. The composition studied consisted of carbon black as the conductive material and polypropylene as the thermoplastic. A filament with a composition of 40% carbon black and 60% polypropylene was obtained. Using square-wave voltammetry, using electrodes printed from this filament as the working electrode, colchicine was determined in tap, bottle, and river water samples. The analytical method showed a linear response range between 2 and 50 µmol L-1, an LD of 10 nmol L-1, and recoveries above 90%, while the preconcentration method showed a factor of 130.