催化荧光光度法测定痕量钼(Ⅵ)

Catalytic Fluorophotometric Determination of Molybdenum(Ⅵ) Based on Fluorescence Quenching Effect

基于在磷酸介质中,钼(Ⅵ)催化过氧化氢氧化碘化钾产生游离碘,并进一步与吖啶橙反应导致其荧光猝灭,据此提出荧光光度法测定痕量钼(Ⅵ)的一种灵敏的方法。采用固定时间法测得在446 nm(λ_(ex))及505 nm(λ_(em))波长处反应体系的△F(即F_0与F值之差)与钼(Ⅵ)的质量浓度在0.16～2.4μg·L^(-1)范围呈线性关系。方法的检出限(3s/k)为0.10μg·L^(-1)。该方法应用于绿豆、茶叶和矿泉水中钼的测定,测得方法的回收率在93%～99%之间,测定值的相对标准偏差(n=5)均小于5%。

Based on the catalytic action of Mo（Ⅵ） on the oxidation of KI by H2O2 in dilute Ha PO4 medium to give free iodine （in form of I3^-） which in turn reacted with acridine orange leading to quenching of fluorescence of acridine orange, a fluorophotometric method for determination of Mo （Ⅵ） was proposed. Linear relationship was found between values of AF（F0--F） determined at wavelengths of 446 nm （λex） and 505 nm （λex） and concentration of Mo（Ⅵ） in the range of 0. 16--2. 4μg·L^-1. Limit of detection （3s/k） of the method found was 0. 10μg·L^-1. The proposed method was used in the determination of Mo（Ⅵ） in samples of green bean, tea and mineral water, giving values of recovery ranged from 93%--99%, and of RSD＇s （n=5） less than 5%.