A sensitive fluorescent probe based on dithizone‐capped ZnS quantum dots for quercetin determination in biological samples

Abstract

A simple turn on/off fluorescence approach based on dithizone‐capped ZnS quantum dots (ZnS@DZ QDs) with the help of lead ions as a fluorescent probe for the quantitative determination of quercetin is reported. The interaction of lead ions with dithizone led to the formation of a rigid structure on the surface of ZnS@DZ QDs and turned on the fluorescence intensity of the QDs. After addition of quercetin to this probe and interaction with lead ions, the fluorescence emission turned off. Concerning the quenching fluorescence intensity of ZnS@DZ QDs/Pb2+ QDs probe induced by the target, under the optimum conditions, the probe enabled detection of quercetin in the concentration range from 0.54 μM to 21.7 μM with a correlation coefficient of 0.993 and detection limit of 0.25 μM. The present probe was applied successfully to the determine quercetin as a nutritional biomarker in human serum and 24‐h urine samples.

Enhanced electrochemical determination of quercetin in a choline chloride-based ionic liquid

“…[1][2][3] In the food industry and pharmaceutical applications, it is necessary to develop smart and selective systems for quercetin determination. Numerous analytical methods have been employed, including high-performance liquid chromatography, 4-6 spectrophotometry, [7][8][9] capillary electrophoresis, 10,11 and electrochemical techniques. [12][13][14][15] Simple instrumentation, fast response, and high sensitivity make electrochemistry a possible way out.…”