The identification of volatile organic compounds (VOCs) as biomarkers has gained significant attention as a non-invasive point-of-care (POC) diagnostic route. VOC concentrations in the human body offer insights into pathophysiological states and aid in the detection of various diseases. This research article focuses on the synthesis of TiO2 Nanocubes (TNC) and TNC@Polyaniline nanocomposite (TNCP) via sol–gel and in-situ polymerization. Structural and morphological analyses were conducted using XRD, FESEM, and TEM techniques. Additionally, disposable screen-printed carbon electrodes (SPCE) were employed to investigate the electrochemical behaviour. The TNCP/SPCE-based VOC biomarkers exhibited exceptional performance, including a remarkably low detection limit of 0.002 µM and a superior sensitivity of 2869.76 µA mM−1cm−2 within the linear range of 1–1000 μM. These results demonstrate that TNCP holds significant potential as a superior VOC biomarker in biomedical applications, particularly for diabetic diagnosis.