Abstract: Test paper, a type of paper product chemically treated to produce color changes in response to specific substances, serves as a valuable tool for rapid detection and analysis. This experiment, based on the surface modification of glass fiber filter paper, introduces a heavy metal ion detection test paper designed with the fluorescence sensing characteristics of rare earth complexes. The test paper demonstrates its effectiveness and convenience in detecting heavy metal ions in water sources. The innovative test paper proves highly useful in addressing heavy metal ion contamination in water, emphasizing the significant role of chemistry in advancing ecological civilization. The simplified, safe, and environmentally friendly process of creating the test paper yields a practical and user-friendly product. This experiment not only educates on the general production and testing principles of test papers but also sparks students’ interest in scientific exploration and application. The experiment, characterized by its simplicity, repeatability, low entry barrier, environmental friendliness, and safety, possesses a unique color aesthetic, leaving a lasting impression. It is suitable for conducting popular science experiments in public places and promoting awareness in experimental teaching across various educational levels.

Key words: Test paper, Metal ion detection, Sensing, Rare earth element, Popular science experiment