A cross-reactive colorimetric sensor array based on AuAg nanocluster-Au nanoparticle interactions for sulfide sensing and Baijiu classification.

Sulfur-containing compounds are important aroma contributors in Baijiu because of their low odor thresholds and strong sensory effects. A cross-reactive colorimetric sensor array based on positively charged Au nanoparticles and negatively charged AuAg nanoclusters was developed for sulfur-containing analyte discrimination and Baijiu classification. Analyte-induced perturbation of the nanoparticle-nanocluster assemblies generated differential optical fingerprints across four sensing elements. Combined with pattern-recognition analysis, the array discriminated seven sulfur-containing analytes at different concentrations and quantified glutathione over 0.1-50 mM. It also classified 16 commercial Baijiu samples and distinguished Baijiu from five other distilled liquors and 50% ethanol. Blind-sample prediction accuracies reached 93.8% for the 16 Baijiu categories and 97.6% for the 21 distilled-liquor categories. Correlation analysis showed associations between selected sensing channels and Baijiu sensory attributes. The proposed array provides a rapid optical fingerprinting approach for Baijiu differentiation and authenticity-related screening.