近年来, 三维荧光技术已经成为常用的化学分析技术, 但有些结构相近的荧光有机物的三维荧光光谱十分相似, 可能导致分析结果错误。 因此, 如何精准区分具有相似三维荧光光谱的有机物是十分重要且亟待解决的问题。 荧光量子产率和荧光寿命是荧光有机物两个重要的光学参数, 对于分子结构的差异更灵敏。 对吲哚、 3-甲基吲哚和L-色氨酸的三维荧光光谱、 荧光量子产率和荧光寿命进行了研究。 结果表明, 它们的三维荧光光谱都出现两个荧光峰, 且荧光峰位置十分接近。 吲哚和L-色氨酸的荧光峰大致位于［激发波长, 发射波长］=［275, 340～350］和［220, 340～350］ nm附近, 3-甲基吲哚的荧光峰位于［激发波长, 发射波长］=［280, 365］和［225, 365］ nm附近。 在相同浓度下, 三种有机物在激发波长为275～280 nm处的最高荧光强度依次为: 吲哚>3-甲基吲哚>L-色氨酸。 利用绝对量子产率测量技术测得吲哚、 3-甲基吲哚和L-色氨酸的荧光量子产率分别约为0.264、 0.347和0.145; 利用时间相关单光子计数技术测得吲哚、 3-甲基吲哚和L-色氨酸的荧光寿命分别约为4.149、 7.896和2.715 ns。 研究表明, 荧光寿命和荧光量子产率能区分三维荧光光谱相似的荧光有机物, 研究结果在荧光有机物的准确识别上具有重要的价值。

In recent years, the fluorescence excitation-emission matrix (EEM) technique has become common for chemical analysis, but fluorescent organic matters with similar structures may exhibit extremely similar EEMs, which may mislead the analysis results. Thus, precisely distinguishing the organic matters with similar EEMs is an important problem to solve. Fluorescence quantum yield (FQY) and fluorescence lifetime (FL) are two important optical parameters for EEM, which are more sensitive to the difference in molecular structure. This study investigated the EEM, FQY, and FL of indole, 3-methylindole, and L-tryptophan. The result showed that their EEMs all displayed one emission (Em) maxima corresponding to two excitation (Ex) maxima, and the position is very close. The fluorescence peaks of indole and L-tryptophan were roughly located at Ex/Em=［275, 340～350］ and ［220, 340～350］ nm, the fluorescence peaks of 3-methylindole were roughly located at Ex/Em=［280, 365］ and ［225, 365］ nm. At the same concentration, these three compounds maximum fluorescence intensity (MFI) at Ex = 275~280 nm followed this sequence: indole>3-methylindole>L-tryptophan. The integral sphere technique evaluated the FQYs of indole, 3-methylindole and L-tryptophan as 0.264, 0.347, and 0.145, respectively. The FLs of indole, 3-methylindole and L-tryptophan were determined as 4.149, 7.896 and 2.715 ns, respectively. This study indicated that the FQY and FL can distinguish fluorescent organic matters with similar EEMs. The results are of great value in accurately identifying fluorescent organic matters.