LASER ABLATION/SUPERSONIC BEAM/MULTIPHOTON IONIZATION/MASS SPECTROMETRY OF CHEMICAL SPECIES RESULTING FROM BIOLOGICAL AND SYNTHETIC POLYMERS

反射飞行时间质谱仪的质量分辨率有了很大的提高，它很容易使含氯化合物的分配成为可能。此外，通过将电离室温度降低到液氮温度来减小背景信号。通过将光学参量振荡器的二次谐波发射转换为受激拉曼散射，使真空紫外区的光谱测量成为可能。首先，我们比较了热分解和激光烧蚀两种方法在制备超音速射流光谱样品中的应用。我们发现激光烧蚀技术更有效地提供了母体离子和热分解技术提供了二聚体和三聚体离子。我们还将该技术应用于作为包装材料的聚苯乙烯泡沫塑料热分解形成的油，发现其中含有多种化学物质，如聚苯乙烯、甲苯、苯等。当我们将飞秒准分子激光脉冲（500 fs, 248 nm）应用于由合成（如乙烯）和生物（如腺嘌呤）聚合物产生的热分解产物时，我们发现与使用纳秒脉冲的情况相比，母体分子更有效地形成。因此，发现短激光脉冲在测定分子量方面是有用的。为了将本方法应用于真实样品，有必要开发一种从光谱中观察到的信号峰分配化学物质的方法。我们使用波长计构建了一个数据库，使光谱测量精度达到1/1000000。我们还提出了一种根据标准品与样品的光谱相似性来确定化学物质种类的新方法。

The mass resolution of the reflectron time-of-flight mass spectrometer was greatly improved, and it readily allowed the assignment of the chlorine-containing compounds. Furthermore, the background signal was reduced by decreasing the temperature of the ionization chamber to a liquid nitrogen temperature. By converting second harmonic emission of the optical parametric oscillator with stimulated Raman scattering, spectrometric measurements in the vacuum ultraviolet region became possible.First, we compared thermal decomposition and laser ablation methods in preparatioin of the sample for supersonic jet spectrometry. We found that the laser ablation technique provides a parent ion more efficiently and the thermal decomposition technique dimer and trimer ions. We also applied the present technique to the oil formed by thermal decomposition of polystirene foam used as packing materials, and found to contain various chemical species such as stirene, toluene, benzene, etc. When we applied a femtosecond excimer laser pulse (500 fs, 248 nm) to thermally decomposed products resulting from synthetic (e.g.stirene) and biological (e.g.adenine) polymers, we found that parent molecules were more efficiently formed in comparison with the case using a nanosecond pulse. Therefore, a short laser pulse was found to be useful in determination of a molecular weight.In order to apply the present method to authentic samples, it is necessary to develop a method to assign chemical species from the signal peaks observed in the spectrum. We constructed a database using a wavemeter allowing the spectrometric measurements in an accuracy of 1/1000000. We also proposed a new method to assign the chemical species from the similarity of the spectra between the standard and the sample.