吖啶橙-罗丹明B荧光共振能量转移猝灭法测定砷

研究了利用吖啶橙(AO)-罗丹明B(RB)共振能量转移荧光猝灭法测定痕量砷的方法。在λ_ex/λ_em=470/580 nm，0.016 mol·L-1 H₂SO₄溶液中，十二烷基苯磺酸钠(DBS)存在下，吖啶橙-罗丹明B能够发生有效的能量转移，使罗丹明B的荧光强度大大增强;在酸性条件下，砷与钼酸铵生成砷钼杂多酸使能量转移体系罗丹明B的荧光猝灭。利用吖啶橙-罗丹明B能量转移荧光猝灭法测定痕量砷，砷在0.01～0.25 mg·L-1范围内与罗丹明B荧光猝灭程度呈良好的线形关系，方法检出限为2.56 μg·L-1。该方法用于茶叶中痕量砷的测定，相对标准偏差为0.48%～0.64%，回收率为98%～103%，结果满意。

Fluorescence Resonance Energy Transfer Quenching Method for Determination of Arsenic with Acridine Orange-Rhodamine B

A new method for the determination of trace arsenic was developed by using fluorescence resonance energy transfer from acridine orange (AO) to rhodamine B (RB). It was found that under the condition of lambda(ex)/lambda(em) = 470/580 nm, effective energy transfer could occur between AO and RB in the dodecyl benzene sodium sulfonate solution. The fluorescence intensity of RB was diminished by molybdoarsenide which was formed by the reaction of arsenic (V) with molybdate in sulfuric acid medium. The detection limit of this method was 2. 56 microg x L(-1). This method was used for the determination of trace arsenic in tea. The range of determination for arsenic was 0.01-0.25 mg x L(-1). The relative standard deviation for the determination of arsenic was 0.48%-0.64%. The recoveries for the addition of 0.01-0.03 mg x L(-1) arsenic were 98%-103%. The method has been applied to the determination of arsenic with satisfactory results.