Ultratrace Analysis Using Semiconductor Laser as an Exciting Source

半导体激光器体积小、强度高、价格便宜，而且易于操作。然后，我们开发了一种分析方法，使用这种半导体激光器进行痕量分析.基于半导体激光荧光的高效液相色谱（HPLC）：我们开发了一种微流动池，由熔融石英毛细管和光纤组成。对于近红外荧光染料，获得的检测极限为12 fg（fg = <10^（-15）> g）。样品经高效液相色谱分离后，用半导体激光荧光法检测近红外染料。用吲哚菁绿色标记人血清中的蛋白质，用高效液相色谱法分离。用这种方法我们可以检测到1.3 pmol的白蛋白。为了对生物分子进行检测，我们发展了一种基于近红外荧光和酶反应的分析方法。我们发现吲哚菁绿色的荧光强度随浓度的增加而减弱<H_2><O_2>。然后，我们可以在黄嘌呤存在下测量黄嘌呤氧化酶的活性。我们可以在0-1单位之间建立一个分析曲线。使用光纤的热透镜分光光度法：在近红外区域，观察到由于泛音振动引起的吸收带。本文提出了一种利用双光纤的热透镜分光光度法。使用多模光纤的方法具有良好的耦合效率，但是输出光束轮廓非常差，从而产生差的聚焦特性。因此，它不适合灵敏检测。另一方面，使用单模光纤的方法具有良好的空间分布，并且灵敏度比传统吸收光谱法高出约50倍。

A semiconductor laser is small, intense, less expensive, and can be easily operated. Then, we developed an analytical method using this semiconductor laser for trace analysis.1. High-performance liquid chromatography (HPLC) based on semiconductor laser fluorimetry: We developed a micro-flow cell, consisting of a fused silica capillary and an optical fiber. The detection limit obtained was 12 fg (fg = <10^(-15)> g) for a near-infrared fluorescent dye. After sample separation by HPLC, we detected near-infrared dyes by semiconductor laser fluorimetry. The detection limit was 0.3 pg. We labeled protein in human serum with indocyanine green and separated by HPLC. By this method we could detect 1.3 pmol of albumin. In order to measure biological molecules, we developed a new analytical method based on near-infrared fluorimetry and enzyme reaction. We found that the fluorescence intensity of indocyanine green decreases with increasing the concentration of <H_2> <O_2> . Then, we could measure the activity of xanthine oxidase in the presence of xanthine. We could construct an analytical curve between 0-1 unit.2. Thermal lens spectrophotometry using optical fibers: In the near-infrared region absorption bands due to overtone vibrations are observed. We developed thermal lens spectrophotometry using a couple of optical fibers. The method using a multimode optical fiber has a good coupling efficiency but the output beam profile was very poor giving poor focal properties. Then, it was unsuitable for sensitive detection. On the other hand the method using a single mode optical fiber has a good spatial profile, and it was about 50 times more sensitive than conventional absorption spectrometry.