DESENVOLVIMENTO DE CÉLULA ELETROQUÍMICA E ELETRODO DE TRABALHO IMPRESSOS PARA DETERMINAÇÃO DE ÁCIDO INDOL-3-ACÉTICO

Abstract

Additive manufacturing, commonly known as 3D printing, has aroused great interest among researchers due to the speed and low cost of designing and producing new materials. The raw material used in the printing process (filament) is diverse, which increases, even more, the interest of many areas, such as electrochemistry, which can print systems for identification and quantification of compounds by electroanalytic. In this study, we used a 3D printer to produce an electrochemical cell for batch injection analysis (BIA) with a non-conductive filament, and a working electrode with a conductive filament. For cyclic voltammetry and amperometry analyses, we used a homemade potentiostat, Ag/AgCl (3 M KCl) reference electrode, platinum auxiliary electrode, and the printed working electrode. The working electrode was characterized by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy and treated with mechanical and electrochemical activation before the standardization of the indole-3-acetic acid (IAA) analysis method. From the cyclic voltammetry results, the potential of -0.4 V was chosen for the amperometric analysis of the IAA. The following analytical characteristics were determined: detection limit (0.65 mg L-1) and quantification (2.16 mg L-1), linearity (linear range: 1 – 50 mg L-1; R2 = 0.998) and repeatability (DPR (n = 9) was 0.88 and 1.27 % for 5 and 25 mg L-1, respectively). In summary, the results demonstrate the possibility of using the printed electrode to quantify IAA in real samples by BIA, being a fast and low-cost method.