Unveiling the potential of a discrete titania chemiresistor: broad-spectrum sensing of C1-C4 alcohols and precise C3 isomer discrimination in binary mixtures.

The detection, discrimination, and quantification (DDQ) of volatile alcohols using cost-effective, sensitive, and selective sensors are necessary for ensuring regulatory compliance in environmental monitoring, healthcare, and quality control. Semiconducting metal oxide (SMO) sensors are well known for detecting volatile organic compounds; however, their potential for precise discrimination and quantification remains hardly explored to date. The present study demonstrates the development of a cost-effective intelligent system based on a single titania chemiresistor that not only detects C1-C4 primary alcohols (methanol, ethanol, 1-propanol, and 1-butanol) but also discriminates isomeric C3 alcohols (1-propanol and 2-propanol) and quantifies the isomeric C3 alcohols in binary mixtures. The system demonstrates excellent repeatability and reproducibility of sensing signals. The mechanisms underlying sensor responses to different alcohol vapours are analysed and correlations between the sensing signals and types or concentrations of alcohol vapours are established. Principal component analysis and advanced machine learning algorithms are implemented for establishing the DDQ of alcohol vapours.