School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730101, China.
School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730101, China; Northwest Collaborative Innovation Center for Traditional Chinese Medicine Co-constructed by Gansu Province & MOE of PRC, Lanzhou 730000, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Feb 5;286:122021. doi: 10.1016/j.saa.2022.122021. Epub 2022 Oct 21.
A novel fluorescent sensor was developed in this study based on glutathione-functionalized graphene quantum dots (GQDs@GSH) to detect organophosphorus pesticide residues in Radix Angelica Sinensis. GQDs@GSH was synthesized by a one-step pyrolysis method with a fluorescence quantum yield as high as 33.9% and its structure was characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. GQDs@GSH exhibited excellent fluorescence property showing strong blue fluorescence under UV irradiation. The fluorescence of GQDs@GSH could be quenched by Fe by electron transfer and the quenched fluorescence could be recovered due to the strong chelating and reducing ability of phytic acid (PA). Under the catalyzation of acetylcholinesterase (AChE) and choline oxidase (ChOx), acetylcholine (ACh) could be decomposed to HO, which could further oxidize Fe to Fe thus quenching the fluorescence of GQDs@GSH once again. Coumaphos, a kind of organophosphorus pesticide, could inhibit AChE activity, thus making the quenched fluorescence turn on again. Several parameters influencing the fluorescence response such as Fe, PA, ACh and coumaphos concentration, pH value and reaction time were optimized. Based on such a fluorescence "off-on-off-on" ngkmechanism, GQDs@GSH was successfully applied to the detection of coumaphos in Radix Angelica Sinensis. A good linear relationship between the fluorescence intensity and coumaphos concentration was obtained in the range of 0.1-10.0 μmol·L. By a standard addition method, the recoveries were measured to be 101.44-117.90% with RSDs lower than 1.98%. The biosensor system is simple, sensitive and accurate. It has a good application prospect in the detection of organophosphorus pesticide residues in traditional Chinese medicine and agricultural products, and also expanded the application scope for glutathione as a highly selective biological molecule.
本研究基于谷胱甘肽功能化石墨烯量子点（GQDs@GSH）开发了一种新型荧光传感器，用于检测当归中的有机磷农药残留。GQDs@GSH 通过一步热解法合成，荧光量子产率高达 33.9%，其结构通过透射电子显微镜和 X 射线光电子能谱进行了表征。GQDs@GSH 表现出优异的荧光性质，在紫外光照射下显示出强烈的蓝色荧光。GQDs@GSH 的荧光可以通过电子转移被 Fe 猝灭，而植酸（PA）的强螯合和还原能力可以恢复猝灭的荧光。在乙酰胆碱酯酶（AChE）和胆碱氧化酶（ChOx）的催化作用下，乙酰胆碱（ACh）可以分解为 HO，HO 可以进一步将 Fe 氧化为 Fe，从而再次猝灭 GQDs@GSH 的荧光。保棉磷是一种有机磷农药，可以抑制 AChE 活性，从而使猝灭的荧光再次开启。优化了影响荧光响应的几个参数，如 Fe、PA、ACh 和保棉磷浓度、pH 值和反应时间。基于这种荧光“关-开-关-开”机制，成功地将 GQDs@GSH 应用于当归中保棉磷的检测。在 0.1-10.0 μmol·L 范围内，荧光强度与保棉磷浓度之间呈现出良好的线性关系。通过标准加入法进行测定，回收率为 101.44-117.90%，RSD 低于 1.98%。该生物传感器系统简单、灵敏、准确，在中药材和农产品中有机磷农药残留的检测方面具有良好的应用前景，也扩展了谷胱甘肽作为高选择性生物分子的应用范围。
