Differentiating Oligosaccharide Isomers via Infrared Spectra of Gaseous Ions

佛罗里达大学的John Eyler教授和他的团队得到了分析和表面化学计划的支持，该计划旨在通过质谱学研究结构异构体的差异化。这些物种具有不同的化学结构，但质量相同，因此通常无法通过质谱学来区分它们。Eyler小组使用傅里叶变换离子回旋共振(FTICR)质谱仪和一些不同的激光器，利用红外多光子解离技术获得了几个波长范围内异构体离子的红外光谱。使用的激光器包括荷兰的一个可广泛调谐的自由电子激光器和佛罗里达大学的三个激光器--一个连续可调的光学参量振荡器(OPO)激光器和线路可调的CO和CO2激光器。模型分析物是碳水化合物及其产物离子，一组具有大量立体异构体的分子。光谱结果与红外光谱的理论计算相辅相成，以确定哪些简正波对吸收带有贡献。数据挖掘技术增强了区分异构体物种的能力。这些活动有助于培养新的化学家，通过本科生的参与吸引新的科学家，并开发用于利用质谱学进行分子异构体识别的通用方法和为国际社会服务的有价值的用户设施。本科生的研究经验涉及国际部分，因为暑期项目是在密歇根大学和荷兰的自由电子激光红外实验(Felix)设施进行的，并与涉及该设施的国际研究和教育伙伴关系(PIRE)计划相结合。

Prof. John Eyler and his group at the University of Florida are supported by the Analytical and Surface Chemistry Program to study the differentiation of structural isomers by mass spectrometry. These species have different chemical structures but identical mass, so they ordinarily cannot be distinguished by mass spectrometry. The Eyler group uses Fourier transform ion cyclotron resonance (FTICR) mass spectrometers and a number of different lasers to obtain the infrared spectra of isomeric ions in several wavelength regions using the technique of infrared multiple photon dissociation. Lasers used include a widely tunable free electron laser in The Netherlands and three lasers at the University of Florida - a continuously tunable optical parametric oscillator (OPO) laser and line tunable CO and CO2 lasers. Model analytes are carbohydrates and their product ions, a group of molecules having an immense number of stereoisomers. Spectral results are supplemented with theoretical calculations of infrared spectra, to determine which normal modes contribute to absorption bands. Data mining techniques enhance the ability to differentiate isomeric species.These activities serve to train new chemists, to attract new scientists via participation of undergraduates in research, and to develop methodology of general use for isomeric discrimination of molecules by mass spectrometry and valuable user facilities serving the international community. The undergraduate research experience involve an international component, as summer projects are carried out both at UF and at the free electron laser for infrared experiments (FELIX) facility in The Netherlands, in conjunction with a Partnerships for International Research and Education (PIRE) program which involves that facility.