DEVELOPMENT OF A NOVEL DETECTION METHOD FOR SINGLE NONFLUORECSECT MOLECULES IN LIQUID SOLUTIONS

分析化学的最终目标之一是检测液体溶液中的某些目标分子并原位观察分子行为。尽管基于生物物种的单分子检测的技术开始提供关于生命工作方式的各种新的和基本的信息，但是目标分子限于非常高荧光的物种，即使对于简单溶液中的分子检测也是如此。大部分生物和环境重要的化学物质，如氨基酸、核苷酸、蛋白质、激素等，都是天然非荧光的。因此，我们的目标是通过提高光热光谱技术的性能，开发超灵敏的检测方法，在液体溶液中的非荧光分子。光热光谱法是一种灵敏的检测液体溶液中非荧光化学物种的方法，我们已经报道了光热信号被双色萃取增强，B ...更多信息 基于光吸收分子的瞬态吸收和非辐射弛豫。我们已经实验研究了生物学上重要的化学物质，氨基酸和核苷酸的吸收光谱，并从理论上估计这些化学物质的瞬态吸收光谱。结果表明，紫外光和可见光或近红外光同时激发可引起光热信号增强。我们提出了一个交叉光束配置作为一个合适的光学设置的紫外-可见光同时激发，并实验证实，光热信号增强的双色激发观察交叉光束的激发配置。我们设计并构建了紫外-可见双色激发光热检测器，并对氨基酸和某些药物在溶液中的光热信号增强进行了实验研究。在与微型HPLC和检测器相结合，我们已经证明了非荧光生物样品的灵敏分离分析。这些结果已经并正在发表在科学文献中。少

One of the ultimate goals of analytical chemistry is to detect certain target molecules in liquid solutions and to observe molecular behavior in-situ. Although techniques based on single molecule detection of biological species begin to provide a variety of new and essential information on the way life works recently, the target molecules are limited to exceptionally highly fluorescent species even for molecule detection in a simple solution. The greater parts of biologically and environmentally important chemicals, such as amino acids, nucleotides, proteins, hormones and so on, are natively nonfluorescent. Thus, we aim to develop ultrasensitive detection methods for nonfluorescent molecules in liquid solutions by improving performance of photothermal spectroscopic techniques. Photothermal spectroscopy is one of the most sensitive detection methods of nonfluorescent chemical species in a liquid solution, and we have reported that photothermal signal is enhanced by two-color exaction, b … More ased on transient absorption and nonradiative relaxation of photoabsorbing molecules. We have experimentally examined absorption spectra of biologically important chemicals, amino acids and nucleotides, and theoretically estimated transient absorption spectra of these chemicals. It is concluded that simultaneous excitation by ultraviolet light and visible or near infrared light could cause photothermal signal enhancement. We proposed that a crossed beam configuration as a suitable optical setup for the ultraviolet-visible simultaneous excitation, and experimentally confirmed that photothermal signal enhancement by the two-color excitation is observed in the crossed beam excitation configuration. We have designed and constructed the ultraviolet-visible two-color excitation photothermal detector and experimentally demonstrated the photothermal signal enhancement for amino acids and some medicines in liquid solutions. In a combination with a micro-HPLC and the detector, we have demonstrated a sensitive separation analysis of nonfluorescent biological specimens. These results are and are being published in scientific literatures. Less