Construction of a universal spectrometer for molecular ions equipped with an electrospray ion source

本研究的目的是构建气相分子离子简易谱仪，该谱仪配备电喷雾离子源。我们在荧光光谱仪内放置了一个商业电喷雾离子源，并试图测量电喷雾释放的水/甲醇液滴中色氨酸离子的荧光光谱。色氨酸荧光光谱的波段位置随着电喷雾离子源到测量位置的距离从0到12 nm的增加而从347到366nm移位。我们得出结论，这种红移是由于在离子源之间的液滴到放置在离子源前面的接地板之间的旅行期间甲醇优先蒸发而不是水。我们还尝试通过在真空室中使用加热管来实现溶剂分子从离子中完全汽化，并获得了脱溶剂离子的质谱。

The purpose of this study was to construct a simple spectrometer for molecular ions in the gas phase, which is equipped with an electrospray ion source. We have placed a commercial electrospray ion source inside a fluorescence spectrometer, and tried to measure fluorescence spectra of tryptophan ions in water/methanol droplets emitted from the electrospray. The band position of the fluorescence spectra of tryptophan shifts from 347 to 366 nm with increasing the distance between the electrospray ion source to the measurement position from 0 to 12 nm. We conclude that this red-shift is due to the preferential evaporation of methanol over water during the travel of the droplets between the ion source to a grounded plate placed in front of the ion source. We also tried to achieve complete vaporization of solvent molecules from the ions by using a heated tube inside a vacuum chamber, and we obtained mass spectra of desolvated ions.