催化碘酸钾氧化异硫氰酸荧光素荧光猝灭法测定痕量硒

基于异硫氰酸荧光素(FITC)可发射强而稳定的荧光信号,KIO3能氧化FITC而发生荧光猝灭,Se(Ⅳ)使FITC的荧光强烈猝灭,Se(Ⅳ)的含量与ΔF值呈线性关系,建立催化KIO3氧化FITC荧光猝灭法测定痕量硒的新方法.方法的线性范围为0.012～2.000×10-15g Se(Ⅳ)/mL,工作曲线回归方程ΔF=1.18+72.74CSe(Ⅳ)(×10-15g/mL)(n=6,r=0.9997),检出限为2.1×10-18g/mL(n=11).分别对Se(Ⅳ)浓度0.012和2.000×10-15g/mL进行7次测定,RSD依次为2.8%和3.5%.用于实际样品中痕量硒的测定和人体疾病的诊断与预报,结果满意.同时探讨了催化荧光猝灭法测定痕量硒的反应机理.

Determination of Trace Selenium by Fluorescence Quenching Method Based on Catalytic Oxidiation of Fluorescein Isothiocyanate by Potassium Iodate

Fluorescein isothiocyanate（FITC） can emit strong and stable fluorescence,KIO3 can oxidize FITC and quench the fluorescence signal,Se（Ⅳ） can strongly quench the fluorescence signal of FITC,and the content of Se（Ⅳ） is directly proportional to ΔF.Based on the facts above,a new fluorescence quenching method for the determination of trace Se（Ⅳ） has been established based on the catalytic oxidiation of FITC by KIO3.The linear range of this method was 0.012~2.000×10-15 g Se（Ⅳ）/mL,with a detection limit of 2.1×10-18 g/mL,n = 11,the regression equation of working curve was ΔF = 1.18＋72.74 CSe（Ⅳ）（×10-15 g/mL）,n= 6,r = 0.9997.Samples containing 0.012 and 2.000×10-15 g Se（Ⅳ）/mL respectively were measured for seven times and the RSDs were 2.8 % and 3.5%.It has been satisfactorly applied to the determination of trace Se in real samples and has used to diagnose and forecast human disease.The mechanism for the determination of trace Se（Ⅳ） by catalytic fluorimetry was also discussed.