基于off-on机理的罗丹明Ag^+荧光探针合成与识别性能

Synthesis and Ag^+ Recognition of a Rhodamine Fluorescent Probe Based on off-on Mechanism

以罗丹明6G、香草醛、氯丙烯等为原料,经过三步反应,合成了一种基于off-on机理的罗丹明荧光探针(RP)。用红外、核磁光谱等技术对其结构进行表征,利用紫外、荧光光谱等研究其光化学性质及识别性能,同时考察了金属离子浓度等因素的影响。结果表明,探针本身荧光很弱,与Ag^+结合后荧光显著增强,在C_2H_5OH/H_2O(1/3,V/V)体系中,荧光探针在689 nm处,对Ag^+具有专属识别性能,受常见金属离子(Cu^(2+)、Hg^(2+)、Pb^(2+)、Cr^(3+)、Cd^(2+)、Fe^(3+)、Co^(2+)、Bi^(3+)、K^+、Na^+)干扰小,探针的荧光强度与Ag^+浓度(26.57~66.20mmol×L^(-1))有良好的线性关系,相关系数R^2=0.9912,检出限达16.09mmol×L^(-1)。Job’s曲线表明,荧光探针与Ag^+的络合比为1:1,同时探讨了响应机理。

A rhodamine fluorescent probe（RP） was synthesized after three steps based on off-on mechanism using rhodamine 6 G, vanillin and allyl chloride as raw materials. Its structure was characterized by NMR and FI-IR, and the photochemical properties and recognition performance were studied by ultraviolet and fluorescence spectroscopy. Effects of metal ion concentration were also investigated. The results indicate that the fluorescent intensity of the probe is weak, which increases after combination with Ag~＋. The fluorescent probe has exclusive Ag~＋ recognition in ethanol/water（1/3, V/V） solution at 689 nm, which is less affected by metal ions such as Cu^（2＋）, Hg^（2＋）, Pb^（2＋）, Cr^（3＋）, Cd^（2＋）, Fe^（3＋）, Co^（2＋）, Bi^（3＋）, K~＋ and Na~＋. The fluorescent intensity of the probe has a linear relationship with Ag~＋ concentration when the Ag~＋ concentration is in a range of 26.57~ 66.20 mmol×L^（-1）.（R^2=0.9912）. The Ag~＋ detection limit of the probe is 16.09 mmol×L^（-1）. The job＇s plot confirms that Ag~＋ and probe complexation ratio is 1：1 and the recognition mechanism is proposed.