Decha Nattawut, Sirirak Jitnapa, Sooksawat Dhassida, Phonchai Apichai, Pornsuwan Soraya, Tansakul Chittreeya
Division of Physical Science, Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University Hat Yai Songkhla 90110 Thailand
Department of Chemistry, Faculty of Science, Silpakorn University Nakhon Pathom 73000 Thailand.
RSC Adv. 2023 Sep 18;13(39):27663-27671. doi: 10.1039/d3ra04681h. eCollection 2023 Sep 8.
Ascorbic acid (AA) or vitamin C plays multiple crucial roles, particularly as an antioxidant. This essentially biologically active molecule was selectively detected over other reductants by the synthesized profluorescent nitroxide probe ProN6 a switch-on method. After either a hydrogen atom or single electron transfer from AA to nitroxide, the resulting diamagnetic hydroxylamine was rapidly cyclized to form a fluorescent -acylalkoxyamine. This cyclization prevented the reoxidation of the corresponding hydroxylamine to the nitroxide, leading to a high precision of detection. A kinetic fluorescence study indicated that ProN6 exhibited higher reactivity than ProN7. Density functional theory (DFT) calculations indicated that the Gibbs free energy of the AA-induced cascade reductive lactonization of ProN6 was lower than that of ProN5 and ProN7. The designed probe achieved the sensitive and specific detection of AA with detection limits of 77.9 nM and 195.9 μM in solution and on paper, respectively. The utilization of the probe as a paper-based fluorescent sensor demonstrated the good accuracy of the quantitative analysis of AA in commercial supplements.
抗坏血酸（AA）即维生素C发挥着多种关键作用，尤其是作为一种抗氧化剂。通过合成的前荧光氮氧化物探针ProN6（一种开启式方法），这种具有重要生物活性的分子能够在其他还原剂存在的情况下被选择性检测。在一个氢原子或单个电子从AA转移至氮氧化物后，生成的抗磁性羟胺会迅速环化形成荧光酰基烷氧基胺。这种环化作用阻止了相应羟胺重新氧化为氮氧化物，从而实现了高精度检测。动力学荧光研究表明，ProN6比ProN7表现出更高的反应活性。密度泛函理论（DFT）计算表明，AA诱导的ProN6级联还原内酯化反应的吉布斯自由能低于ProN5和ProN7。所设计的探针分别在溶液中和纸上实现了对AA的灵敏且特异性检测，检测限分别为77.9 nM和195.9 μM。将该探针用作基于纸的荧光传感器，证明了其对商业补充剂中AA进行定量分析具有良好的准确性。
