Luminescence Determination of Rutin Using Gold Nanoclusters

A possibility of the luminescence determination of rutin with gold nanoclusters is shown. The approach is based on the luminescence quenching of the nanoclusters by rutin molecules, which occurs when the rutin absorption wavelengths overlap with wavelengths of the nanocluster excitation. The optimal conditions include pH 11–11.5 and ethanol concentration in the reaction mixture 20%; the time after mixing the reagents does not affect the result. Rutin can also be determined by spectrophotometry, and a combination of spectrophotometric and fluorometric signals increases analytical sensitivity. The limits of detection for rutin are 1.6 μM by fluorometry, 0.5 μM by spectrophotometry, and 0.3 μM using a combination of both techniques. The corresponding linear ranges are 4.8–100, 1.5–100, and 0.9–100 μM, respectively. Common inorganic ions, even in concentrations 100 times higher than that of rutin, do not interfere with the determination. The proposed procedure was successfully applied to an analysis of a biologically active supplement.