Resumen de Using Recycled Bacterial Culture Media to Demonstrate Anti-Counterfeiting Measures and Ninhydrin Tests with “Turn Off Fluorescence” to High School Students
There is a need to educate students at the high school level about recycling. Recycled bacterial culture media can be used as ultraviolet (UV) fluorescent ink. We propose two sets of experimental demonstrations; in the first set, an anticounterfeiting demonstration can be performed using this ink in a fountain pen. Enhanced visibility of the handwritten words on filter paper due to strong blue fluorescence can be demonstrated through UVA-360 nm light exposure. Bacterial culture media are rich sources of proteins, so, in the second set, a ninhydrin test can be performed on the filter paper. Turn “off” fluorescence of bacterial culture media can be observed after Ruhemann’s purple color formation. A low-cost handheld UV lamp (4 W, battery operated) is capable of all UV exposure experiments. Through these experimental demonstrations, students will learn about recycling, the potential use of laboratory based redundancies and wastes, fluorescence, anticounterfeiting security inks, turn “off” fluorescence, and a qualitative protein test. Use of recycled bacterial culture media in chemical education is a cost-effective as well as green chemistry approach, and both demonstrations are very informative. Both can be easily demonstrated in school science practical and science exhibitions and may provide a good interactive session for students.
