基于对Fe^(3+)-H_2O_2-OPD体系荧光和比色信号的增强检测多巴胺

Dual-mode Detection of Dopamine Based on Enhanced Fluorescent and Colorimetric Signals of Fe^(3+)-H_2O_2-o-Phenylenediamine System

利用多巴胺对Fe^(3+)-H_2O_2-OPD体系荧光和比色信号的增强,建立了一种荧光和比色双模检测的多巴胺传感方法。Fe^(3+)催化H_2O_2氧化无色的邻苯二胺(OPD),生成黄色且具有荧光信号的二氨基吩嗪(DAP),但是该反应很慢。多巴胺通过引发芬顿反应,促进Fe^(3+)-H_2O_2体系持续产生强氧化性的羟基自由基(·OH),从而加快了OPD转化成DAP的速率,使体系溶液颜色加深,荧光增强。基于此原理,通过测量Fe^(3+)-H_2O_2-OPD体系荧光和比色信号随多巴胺浓度的变化,可以实现多巴胺的双模检测。本方法荧光和比色检测多巴胺的线性范围分别为0.05~20#mol/L和0.10~18#mol/L,检出限分别为15 nmol/L和65 nmol/L(S/N=3)。荧光和比色双模式检测方法操作简单、灵敏度高、结果可视化,并增加了检测的准确度。将本方法应用于人尿液中多巴胺的检测,结果良好。

A dual-mode＂light-on＂assay platform based on enhanced fluorescent and colorimetric signals of Fe3＋-H2O2-OPD system for detection of dopamine was designed.Fe3＋can catalyze the H2O2-mediated oxidation of colorless and nonfluorescent o-phenylenediamine（OPD）,and the resultant of 2,3-diaminophenazine（DAP）exhibits a visible yellow color,emitting a yellow fluorescence.However,the reaction rate is extremely slow.When dopamine is introduced,it involves a Fenton type reaction which generates hydroxyl radical（·OH）continuously,thus increasing the conversion rate of OPD to DAP.Correspondingly,both color and fluorescence of the sensing system are enhanced obviously.On the basis of this fact,a sensor with dual-readout for the detection of dopamine is established via measuring the fluorescent and colorimetric signals of the Fe^3＋-H2O2-OPD system.The linear ranges are 0.05-20nmol/L and 0.10-18nmol/L,and the detection limits are calculated to be 15 and 65 nmol/L（S/N=3）for fluorescent and colorimetric detection,respectively.The fluorescent and colorimetric dual-readout method developed in the present work features simplicity,high sensitivity and visualization,and enhances the detection accuracy of dopamine.Moreover,the method has been successfully applied to detection of dopamine in human urine with satisfactory results.