一种可用于检测pH和H_(2)O的双比率荧光探针

A Double Ratio Fluorescent Probe for pH and Water Detection

pH和水的检测在生命科学和化学工业中是至关重要的。对以中性红(NR)为碳源,乙二胺(EDA)为氮源,乙醇为溶剂,溶剂热法合成的黄色荧光碳点(NR-EDA-CDs)进行了研究,发现该碳点在激发波长为310~370 nm范围时,可以产生双发射峰。由此,建立了基于单一发光剂的双比率荧光探针检测pH和水的方法。通过高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、拉曼光谱、红外光谱(IR)和X射线光电子能谱(XPS)对该碳点进行了表征,表明该碳点的形状为类球形,平均粒径为3.6 nm,有明显的石墨结构。研究发现,在365 nm激发波长下,该碳点具有良好的稳定性、抗光漂白性和耐盐性。在磷酸盐缓冲溶液中,pH值在4.15~8.55范围内与581和449 nm的荧光强度比(F_(581)/F_(449))具有良好的线性关系,其决定系数R^(2)=0.986。该pH比率荧光探针具有线性范围宽和可逆性好等特点。同时发现在二甲基亚砜溶剂中,水的含量在0.6%~50%(V(H_(2)O)/V(DMSO))范围内与F_(485)/F_(585)具有良好的线性,其决定系数R^(2)=0.996,检出限为0.18%(V(H_(2)O)/V(DMSO))。该双比率荧光探针为pH和水的检测提供了一种新的方法。

The detection of pH and water is critical in the life sciences and chemical industries.The yellow fluorescent carbon dots(CDs)synthesized by solvothermal method using neutral red(NR)as carbon source,ethylenediamine(EDA)as nitrogen source and ethanol as solvent was studied.It was found that the carbon dots(NR-EDA-CDs)could produce double emission peaks when the excitation wavelength was in the range of 310~370 nm.Therefore,a method for the detection of pH and water with a double ratio fluorescence probe based on a single luminant was established.The carbon dots were characterized by high-resolution transmission electron microscopy,X-ray diffraction,Raman spectroscopy,infrared spectroscopy and X-ray photoelectron spectroscopy.The results showed that the carbon dots are spheroidal in shape,with an average particle size of 3.6 nm and obvious graphite structure.It was found that the carbon dots has good stability,photobleaching resistance and salt tolerance at the excitation wavelength of 365 nm.In phosphate buffer solution,pH in the range of 4.15~8.55 has a good linear relationship with the fluorescence intensity ratio of 581 and 449 nm(F_(581)/F_(449)),and its coefficient(R^(2))is 0.986.The pH ratio fluorescent probe has the characteristics of wide linear range and good reversibility.At the same time,it was found that the content of water in DMSO is linear with F_(485)/F_(585)in the range of 0.6%~50%(V(H_(2)O)/V(DMSO)),R^(2)is 0.996,and the detection limit is 0.18%(V(H_(2)O)/V(DMSO)).The double ratio fluorescent probe provides a new method for the detection of pH and water.