Bright green cellulose-based fluorescent probe toward Au smartphone technology recognition and its visualization application.

In this study, a novel fluorescent probe, MAC-2, for the detection of Au was designed and synthesised using cellulose as a carrier combined with benzothiazole derivatives. The structure of the probe was confirmed by SEM, XRD, FTIR, and H NMR, also the optical properties of the product were investigated. MAC-2 showed bright green fluorescence under a 365 nm UV lamp and exhibited significant quenching behaviour toward Au. MAC-2 utilises more sustainable biomass resources, featuring green and biodegradable characteristics that meet environmental requirements. Compared with most reported probes, it exhibits notable fluorescence properties. The limit of detection (LOD) is as low as 0.057 μM, and the response time is 1 min. It also demonstrates good specific recognition and anti-interference abilities. In addition, a smartphone was used as a portable signal processing device to achieve rapid detection of Au concentration. Meanwhile, MAC-2 was successfully prepared as a fluorescent test strip, providing a potential application for the convenient detection of Au. The high sensitivity and selectivity exhibited by cellulose-based fluorescent probes in detecting Au offer valuable insights and new ideas for the detection of other metal ions and biomolecules. These inspirations will help promote the continuous development of research and applications in related fields.