酶催化荧光猝灭法测定土壤中痕量硒

Determination of trace selenium in soil by enzymatic catalytic fluorescence quenching method

在牛血红蛋白催化作用下,H2O2能够氧化L酪氨酸产生荧光,而硒对该荧光体系具有较强的猝灭作用.据此,建立了一种酶催化荧光猝灭法测定痕量硒的新方法.实验从pH值、L酪氨酸溶液浓度、H2O2浓度,牛血红蛋白溶液浓度和反应时间等方面进行了探讨.在pH9.8的NH3·H2O NH4Cl缓冲溶液中,当L酪氨酸、H2O2和血红蛋白的浓度分别为7.5×10^-5 mol/L、1.0×10^-4 mol/L和2.0×10^-7 mol/L时,测定硒的线性范围为0.3～50μg/mL,方法的检出限为0.05 μg/mL.方法应用于富硒花生土壤中痕量硒的测定,测定值与原子吸收光谱法的测定值基本一致,相对标准偏差为4.6％～4.9％.

A simple spectrofluorimetric method for the determination of selenium based on the fluorescence quenching of hemoglobin was developed. The influence of acidity, L-tyrosine concentration, H2O2 concentration, hemoglobin concentration and reaction time on the system were studied. In NH3· H2O-NH4 Cl buffer solution of pH 9.8, when the concentration of L-tyrosine, H2 02 and hemo- globin were 7.5× 10 ^-5mol/L,1.0× 10^- 4 mol/L and 2.0× 10^-7 mol/L respectively,the linear range for the determination of selenium was 0.3-50 〉g/mL with the detection limit of 0.05 μg/mL. The proposed method was applied for the determination of selenium in selenium-enriched soil, the results were consistent with those of atomic absorption spectrometry. The relative standard deviation （RSD） was 4.6 -4.9 %.