Betanin-driven Multimodal Sensor Platform for Qualitative and Quantitative Detection of Petrol Adulteration

Fuel adulteration, particularly with kerosene, remains a significant concern affecting engine performance, air quality, and regulatory compliance. In this study, we report the development of a multi-technique analytical platform utilizing betanin, a naturally occurring pigment, for the detection of kerosene adulteration in petrol. A 0.1% betanin solution was prepared and applied to evaluate visual colorimetric changes in adulterated fuel samples at varying kerosene concentrations (5%, 10%, 20%). The detection system employed four analytical approaches: colorimetric analysis, UV-Visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and thin-layer chromatography (TLC) on betanin-coated plates. Colorimetric changes were recorded over 24 hours, showing progressive fading correlated with kerosene content. Spectrophotometric analysis demonstrated a measurable decline in absorbance at 538 nm with increasing adulteration, while FTIR confirmed alterations in functional groups, particularly alcohol- and hydrocarbon-related peaks. TLC analysis revealed increasing spot size with higher kerosene levels, indicating effective chromatographic separation. This integrated method proves that betanin can serve as a sensitive, eco-friendly, and low-cost probe for fuel adulteration detection, suitable for both laboratory validation and potential field deployment.