Abstract: With the continuous expansion of the tea-drinking population in China and the improvement of people's quality of life, premium and high-quality teas have become increasingly popular, leading to a rapid increase in demand. This innovative experiment capitalizes on the varying contents of tea polyphenols and amino acids in teas of different grades. It developed a simple and cost-effective colorimetric sensor array based on the indicator replacement principle for the rapid identification of two grades of Wuyishan rock tea (Niulankeng cinnamon and ordinary cinnamon). The RGB values of images captured through smartphone photography are extracted using MATLAB software, followed by analysis of the RGB data through partial least squares discriminant analysis (PLS-DA). The results demonstrate that this method can quickly and accurately distinguish between different grades of tea, with a classification accuracy of 100%. This innovative experiment addresses practical challenges and is closely aligned with cutting-edge scientific research, effectively enhancing students’ comprehensive experimental skills. The integration of advanced chemometrics and mobile imaging technology not only increases students’ interest in and understanding of subjects like image processing and data analysis, but also boosts their participation in scientific experiments and deepens their critical thinking. Furthermore, due to its reliance on inexpensive equipment and the clear visual effects it provides, the experiment can be applied in the development of comprehensive experimental curricula in universities. This approach could help solve issues such as the shortage of large-scale precision instruments and the monotony of experiments in certain institutions.

Key words: Colorimetric sensor array, Tea grade, Smartphone imaging, Chemometrics