Department of Pharmaceutical Chemistry, College of Pharmacy, Najran University, Najran, Saudi Arabia; Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt.
Department of Pharmaceutical Chemistry, College of Pharmacy, Najran University, Najran, Saudi Arabia.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 May 5;252:119516. doi: 10.1016/j.saa.2021.119516. Epub 2021 Feb 1.
Herein, yellow emissive nitrogen doped graphene quantum dots (N@GQDs) were prepared by a novel advanced thermal driven oxidation. The N@GQDs was functionalized with β-cyclodextrin (β-CD) to improve its catalytic performance towards dopamine (DA) detection. The β-CD/N@GQDs exhibited strong fluorescence at λ = 550 nm after excitation at 460 nm with a quantum yield of 38.6%. The β-CD/N@GQDs showed good peroxidase like activity via catalyzing the oxidation of tetramethylbenzidine (TMB) in presence of HO to form blue colored product at λ = 652 nm. In the colorimetric assay of DA, the detection based on the oxidation of TMB by HO in presence of β-CD/N@GQDs as a catalyst. Then, the color of the blue oxidized TMB (oxTMB) product was reduced by addition of DA. While the fluorometric detection of DA based on the "inner filter effect" of the overlapped emission spectrum of β-CD/N@GQDs with the absorption spectrum of oxTMB, where, addition of DA reduces oxTMB to TMB and restores the fluorescence intensity of β-CD/N@GQDs. Under the optimized conditions, the colorimetric method achieved linearity range of 0.12-7.5 µM and LOD (S/N = 3) of 0.04 µM, while the fluorometric method achieved linearity range of 0.028-1.5 µM and LOD (S/N = 3) of 0.009 µM. The peroxidase like activity of β-CD/N@GQDs was used to detect DA in human plasma and serum samples with good % recoveries. The colorimetric and fluorometric methods exhibited good sensitivity and selectivity toward DA detection.
本文通过一种新颖的先进热驱动氧化法制备了黄色发射氮掺杂石墨烯量子点（N@GQDs）。将 N@GQDs 功能化β-环糊精（β-CD），以提高其对多巴胺（DA）检测的催化性能。β-CD/N@GQDs 在 460nm 激发下，在 550nm 处显示出强烈的荧光，量子产率为 38.6%。β-CD/N@GQDs 通过在 HO 存在下催化四甲基联苯胺（TMB）的氧化，表现出良好的过氧化物酶样活性，在 λ = 652nm 处形成蓝色产物。在 DA 的比色测定中，基于 HO 在存在β-CD/N@GQDs 作为催化剂的情况下氧化 TMB 的检测。然后，加入 DA 会将蓝色氧化 TMB（oxTMB）产物的颜色还原。而基于β-CD/N@GQDs 的重叠发射光谱与 oxTMB 的吸收光谱之间的“内滤效应”的 DA 的荧光检测，其中，加入 DA 将 oxTMB 还原为 TMB，并恢复β-CD/N@GQDs 的荧光强度。在优化条件下，比色法的线性范围为 0.12-7.5µM，LOD（S/N=3）为 0.04µM，而荧光法的线性范围为 0.028-1.5µM，LOD（S/N=3）为 0.009µM。β-CD/N@GQDs 的过氧化物酶样活性用于检测人血浆和血清样品中的 DA，回收率良好。比色法和荧光法对 DA 检测均表现出良好的灵敏度和选择性。
