Ke Ching-Bin, Lu Te-Ling, Chen Jian-Lian
Department of Beauty and Health Care, Min-Hwei Junior College of Health Care Management, No. 1116, Sec. 2, Zhongshan E. Rd., Tainan 73658, Taiwan.
School of Pharmacy, China Medical University, No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan.
Nanomaterials (Basel). 2018 May 26;8(6):372. doi: 10.3390/nano8060372.
Oxygen and nitrogen capacitively coupled plasma (CCP) was used to irradiate mixtures of aliphatic acids in high boiling point solvents to synthesize fluorescent carbon dots (C-dots). With a high fluorescence intensity, the C-dots obtained from the O₂/CCP radiation of a 1-ethyl-3-methylimidazolium dicyanamide ionic liquid solution of citric acid were characterized with an average diameter of 8.6 nm (σ = 1.1 nm), nitrogen and oxygen bonding functionalities, excitation-independent emissions, and upconversion fluorescence. Through dialysis of the CCP-treated C-dots, two emissive surface states corresponding to their respective functionalities and emissions were identified. The fluorescence spectrum of the CCP-treated C-dots was different from that of the microwave irradiation and possessed higher intensity than that of hydrothermal pyrolysis. By evaluation of the fluorescence quenching effect on flavonoids and metal ions, the CCP-treated C-dots showed a high selectivity for quercetin and sensitivity to Hg. Based on the Perrin model, a calibration curve (² = 0.9992) was established for quercetin ranging from 2.4 μM to 119 μM with an LOD (limit of detection) = 0.5 μM. The quercetin in the ethanol extract of the sun-dried peel of cv. Chachiensis was determined by a standard addition method to be 4.20 ± 0.15 mg/g with a matrix effect of 8.16%.
采用氧和氮电容耦合等离子体（CCP）辐照高沸点溶剂中的脂肪酸混合物，以合成荧光碳点（C点）。从柠檬酸的1-乙基-3-甲基咪唑二氰胺离子液体溶液的O₂/CCP辐射中获得的C点具有高荧光强度，其平均直径为8.6 nm（σ = 1.1 nm），具有氮和氧键合官能团、与激发无关的发射以及上转换荧光。通过对CCP处理的C点进行透析，确定了与其各自官能团和发射相对应的两种发射表面状态。CCP处理的C点的荧光光谱与微波辐照的不同，且强度高于水热热解的。通过评估对黄酮类化合物和金属离子的荧光猝灭效应，CCP处理的C点对槲皮素表现出高选择性，对汞表现出敏感性。基于佩林模型，建立了槲皮素在2.4 μM至119 μM范围内的校准曲线（² = 0.9992），检测限（LOD）= 0.5 μM。采用标准加入法测定了茶枝柑陈皮乙醇提取物中的槲皮素含量为4.20±0.15 mg/g，基质效应为8.16%。
