Nanozyme and dye-driven paper-based sensor array: A novel convenient solution for crude baijiu quality discrimination

The quality of crude baijiu significantly influences the flavor and overall quality of the final product. Herein, we developed a novel three-channel colorimetric sensor array integrating methylene blue, Rhodamine B, and methyl orange with reactive radicals (SO₄•^-) generated via a CoCu@g-C₃N₄/PMS system. The sensor accurately discriminated eight reducing substances through PCA, LDA, and HCA. It enabled rapid detection within 60 s and demonstrated good linearity for ascorbic acid (10-5000 μM, LOD: 10 μM). A smartphone-assisted liquid-phase array successfully differentiated 16 crude baijiu samples with 100 % blind test accuracy. Furthermore, a wax-printed paper-based sensor array was constructed, offering cost-effective, portable, and on-site discrimination of baijiu grades. This system presents a practical solution for baijiu quality control and industrial application.