I3^--RhB体系返荧再现测定工业甲醇中乙醇残留

I3^--RhB system for determination of ethanol residues in industrial methanol by fluorescence recovery

碘(I3^-)对罗丹明B(RhB)具有荧光猝灭作用,可使RhB的荧光信号强度减弱甚至消失,而乙醇碘仿反应对I3^--RhB体系具有荧光反猝灭作用,使体系荧光信号再现,且增强程度与乙醇浓度成线性关系,甲醇与碘不反应。在发射波长580 nm处,测量空白液与试液荧光强度之差△F,根据△F值与反应液中的乙醇浓度相关性,建立了一种返荧再现测定工业甲醇中乙醇残留的方法,该方法线性回归方程为△F=-7.621+8.927 c(μmol·L^-1),相关系数R为0.9934,线性范围0~24μmol·L^-1,检出限为3.36×10^-9 mol·L^-1。用本方法对燃料甲醇样品进行测定,测定值均未超过最高限量规定,加标回收率在96~100.4%之间。

When the fluorescence signal intensity of Rhodamine B(RhB)weakens or even disappears by Iodine(I3^-)solution,Ethanol can undergo iodoform reaction,which makes the system fluorescent signal reappear.And there was a linear relationship between the fluorescence signal enhancement degree and ethanol concentration,but methanol does not react with iodine.In this paper,580 nm were chosen as emission wavelength respectively for measurement of the ethanol concentration.According to linear relationship between the value ofΔF and ethanol concentration of sample solution,a new method of fluorescence recovery for the determination of ethanol in industrial methanol was established.Experimental results demonstrated that good linearity of the analyte was observed in the range of 0~24μmol·L^-1 with correlation coefficients(r=0.9934).The linear equation was△F=-7.621+8.927 c(μmol·L^-1),and the limits of detection(LOD)was 3.36×10^-9 mol·L^-1.The fuel methanol tablets were determined by this method,the measured values were within the specified range,and the recovery rate was between 92%and 106%.