叶酸的能量转移荧光测定法及其应用

A Fluorescent Energy Transfer Method and Its Application in the Detection of Folic Acid

报道了一种灵敏检测叶酸的荧光新方法。在叶酸-KMnO4-Eu3+-H2O2体系中,以pH=4.7的乙酸-乙酸钠(浓度为0.2mol/L)为缓冲溶液,利用高锰酸钾和过氧化氢将叶酸氧化形成蝶呤-6-羧酸,与Eu3+配位成配合物,该配合物被激发后,蝶呤-6-羧酸通过分子内能量转移将吸收的能量传递到Eu3+,从而发射出Eu3+的特征荧光。在4×10-8～4×10-5mol/L范围内,Eu3+的荧光强度与叶酸的浓度呈线性关系,相关系数为0.9902,检测限达到1.2×10-8mol/L。用于实际样品中叶酸的检测,得到了满意的结果。

The detection of folic acid by a fluorescent energy transfer method has been developed.In the folic acid-KMnO4-Eu3 ＋-H2O2 system with the presence of HAc-NaAc buffer solution（pH = 4.7,0.2 mol/L）,the folic acid can be oxidized by KMnO4 with the presence of H2O2 and converted into the purine of butterfly-6carboxyl acid,which can coordinate with Eu3 ＋ forming a complex.The experimental conditions including the concentration of buffer solution and pH value,choice of oxidant,the temperature and heating time,the concentration of Eu3 ＋,etc.,were optimized.This system can emit the characteristic fluorescence of Eu3 ＋ through an intra-molecule energy transfer process.The fluorescent intensity is in proportional to the concentration of folic acid in the range of 4 × 10-8 ～ 4 × 10-5 mol/L with correlation coefficient of 0.9902.The detection limit is found to be 1.2 × 10-8 mol/L.The developed method has been successfully applied to the determination of folic acid in the actual samples.