Regional Institute for Applied Chemistry Research (IRICA), 13071, Ciudad Real, Spain.
Department of Analytical Chemistry and Food Technology, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, 13071, Ciudad Real, Spain.
Mikrochim Acta. 2020 Jul 16;187(8):446. doi: 10.1007/s00604-020-04437-x.
Accurate-controlled sized graphene quantum dots (GQDs) have been used as an analytical nanoprobe for detecting curcumin as a function of the photoluminescent quenching upon increasing concentrations of the analyte. Regarding the importance of curcumin nanoparticles in nutraceutical food, the analytical method described herein was also proven for the discrimination of curcumin remaining in free solution from that encapsulated into water-soluble nanomicelles of ca. 11 nm. This recognition is based on the displacement of GQD emission when interacting with both curcumin species. Maximum emission wavelength of GQDs suffers a gradual quenching as well as a red-shifting upon increasing concentrations of free curcumin (from 458 to 490 nm, exciting at 356 nm). On the other hand, in the presence of nanocurcumin, GQD photoluminescent response only displays a quenching effect (458/356 nm). The sensitivity of the described method in terms of detection limits was 0.3 and 0.1 μg mL for curcumin and nanocurcumin, respectively. The applicability of the photoluminescent probe for the quantification and discrimination between both curcumin environments was demonstrated in nutraceutical formulations namely functional food capsules and fortified beverages such as ginger tea. Graphical abstract.
已将精确控制尺寸的石墨烯量子点 (GQD) 用作分析纳米探针，以检测姜黄素作为分析物浓度增加时的光致荧光猝灭的函数。鉴于姜黄素纳米粒子在营养食品中的重要性，本文所述的分析方法还可用于区分游离溶液中残留的姜黄素与水溶性约 11nm 纳米胶束中包封的姜黄素。这种识别基于与两种姜黄素物种相互作用时 GQD 发射的位移。当游离姜黄素浓度增加时，GQD 的最大发射波长逐渐猝灭并发生红移（从 458nm 至 490nm，激发波长为 356nm）。另一方面，在纳米姜黄素存在下，GQD 光致荧光响应仅显示猝灭效应（458/356nm）。该方法在检测限方面的灵敏度分别为 0.3μg/mL 和 0.1μg/mL 用于姜黄素和纳米姜黄素。该光致荧光探针在营养配方中（如功能性食品胶囊和强化饮料如姜茶）定量和区分两种姜黄素环境中的适用性已得到证明。
