A novel colorimetric sensor array for Baijiu discrimination based on gold triangular nanoplates etching

The detection of Baijiu is important because of its essential role in Chinese food culture. In this study, a novel acid- and sulfide-sensitive colorimetric sensor array was constructed for Baijiu discrimination based on the etching of gold triangular nanoplates (Au TNPs). Under acidic conditions, Au TNPs were easily etched by potassium iodide (KI) and hydrogen peroxide (H2O2). The morphology of Au TNPs underwent transitions from triangle to ellipse or round, accompanied by multiple color changes. Acids or sulfides existed in Baijiu could further accelerate or inhibit Au TNPs etching, forming a unique colorimetric response pattern, which would be processed by pattern recognition. With this method, 6 kinds of acids and 7 kinds of sulfides were accurately identified, respectively. Quantitative analysis of glutathione had also been achieved. The Euclidean distance (ED) showed a linear relationship with the logarithm of glutathione concentration in the range of 0.1-10 mM. 16 kinds of Baijiu were successfully discriminated with an accuracy of 100 %. Notably, several interfering alcoholic beverages were also accurately identified. The colorimetric sensor array constructed in this work exhibited the advantages of simplicity of operation, quick response and superior performance, showing potential application prospects either for the real-time or on-site identification of traditional Chinese Baijiu.