PhD student of chemistry Federal University of Minas Gerais Goiânia, Minas Gerais, Brazil
Abstract: In this study, we fabricate compact 3D-printed carbon black (CB) electrodes embedded on polylactic acid (PLA) thermoplastic and introduce a combination of its sensor and voltammetric readout to perform the fast analysis of folic acid (FA) in fruit samples. The proposed sensor was used to evaluate the impact of UV radiation on the photostability of FA. Before application in the FA analysis, the electrodes surfaces were characterized by high-resolution scanning electron microscopy and voltammetry of well-known redox probes. Considering the detection of FA, the herein introduced catalytic material revealed suitable electrochemical aspects, including oxidation potential at ~ 0.77 V vs CB/PLA, diffusional mass-transfer, and fast diffusional coefficient (~ 0.26 x 10-4 cm2 s-1). Square wave voltammetric study presented linear responses in the range between 10 and 200 µmol L-1 (R2 > 0.99), exhibited a suitable detection limit (LD) of ~5.1 µmol L-1 and acceptable performance in terms of reproducibility and anti-interference experiments. The analysis of FA in four different food samples through the proposed method agreed statistically with a comparative technique (spectrophotometric approach). Moreover, the achieved results from photostability experiments indicated that FA can be degraded after 5 and 20 min of UV radiation. These results confirmed the applicability of the 3D-printed electrodes as sensing material and for monitoring the photostability of FA in different fruit matrices.
