Ag-Doped ZnO Quantum Dots for Fluorescence-Based Detection of Trace Cr(VI) from River Water and Fish samples

The co-precipitation process was used to create silver-doped zinc oxide. Fluorescence spectrophotometry, XRD, FT-IR, BET, TGA, and UV-Vis were used to characterize it. When stimulated at 360 nm, the Ag/ZnO QDs displayed intense fluorescence emission at 508 nm and were highly selective for Cr(VI). A calibration curve was plotted for different concentration levels of Cr(VI) ranging from 0 to 12 mg/L, with an R² value of 0.998 and the LOD and LOQ at 3.2 µg/L and 11 µg/L, respectively. Three concentration levels, 0.8, 5.6, and 10.4 mg/L, were used to examine the precision of the devised approach; relative standard deviation values did not surpass 5.4%, showing good reproducibility. By adding known quantities of Cr(VI) to the water and fish samples, the method’s recovery was assessed; the results ranged from 77.5% to 112.5%. Ultimately, the suggested approach demonstrated outstanding sensitivity, selectivity, and repeatability for the detection of Cr(VI) in fish and water samples.