Synthesis and characterization of GO-H3BO3 composite for improving single-sensor impedimetric olfaction

The present study shows the synthesis and characterization of graphene oxide (GO) and its composite with boric acid (GO-HBO). Their films were applied to a multi-frequency impedimetric single-sensor olfaction, operating in a high humid environment for human breath diagnoses. The characterization of the composite GO-HBO and bare GO was carried using scanning electronic microscopy (SEM), impedance spectroscopy (IS), structural analysis: XRD, Raman, and elementary analysis: X-ray photoelectron spectroscopy (XPS) and thermogravimetry (TG). The determination of the electronic signatures of the water and aqueous solutions of ethanol or acetone, in the range of 80–640 ppm, was carried out. For that, a single sensor was interrogated sequentially with five different frequencies of the signal probe, inside a headspace system. The matrix of values, of the impedance, capacitance, and phase angle, was analyzed using multivariate PCA statistics. The differential performance of both materials was discussed based on structural and electric properties. Despite the proof-of-concept nature of this study, the whole of its results contributes to the further developments of materials for single-sensor olfaction.