Copper nanoclusters combined with polymer films as highly sensitive colorimetric probes for visual and proportional fluorescence detection of hexavalent chromium ions in pH and natural waters

In this study, a novel type of fluorescent nanocomposite film was prepared, which could be used for pH value sensing and detecting heavy metal hexavalent chromium ions. Copper nanoclusters doped into polyvinyl alcohol polyethylene glycol fluorescent nanocomposite film (CuNCs/PVA/PEG) has excellent fluorescent properties; it can not only be used as a pH sensor but also can selectively detect heavy metal hexavalent chromium ions. When pH>9, the CuNCs/PVA/PEG composite film will be quenched, which can be used as pH sensing. In addition, the CuNCs/PVA/PEG composite film can detect heavy metal hexavalent chromium ions with a detection line of 0.01 μM. It shows that the probe can detect Cr6+ quickly, sensitively, and selectively and has broad application prospects in environmental analysis applications. [Display omitted] •The prepared CuNCs/PVA/PEG fluorescent composite film is hydrophilic, flexible, stable and has long-wave emission properties in the red light region.•It can rapidly detect Cr(VI) in natural water with a detection limit of 0.01 μM.•CuNCs/PVA/PEG fluorescent composite membranes are green and non-hazardous and allow rapid real-time monitoring of Cr(VI) ions in natural water.•CuNCs/PVA/PEG fluorescent composite films have a good response to pH, and great application prospects.