A Novel Scan Method for Differential Ion Mobility Spectrometry Separations (2015)

Undergraduates: Rachel Harris, Brandon G. Santiago, Samantha L. Isenberg Gary L. Glish

Faculty Advisor: Gary Glish
Department: Chemistry

---

The analysis of complex mixtures by mass spectrometry often leads to convoluted spectra in which it is difficult identify compounds of interest. Oftentimes, pre-ionization separation techniques such as liquid chromatography are used prior to mass spectrometric analysis. As an alternative to pre-ionization separations, post-ionization, gas phase separations such as differential ion mobility spectrometry (DIMS) can be coupled to mass spectrometry to improve signal-to-background. While nitrogen is typically used as the DIMS carrier gas, helium can be added to improve the resolution of these separations. However, the addition of helium also leads to a loss of ion transmission, especially for ions of higher differential ion mobility. In an effort to improve both the resolution and ion transmission of DIMS separations the ¿¿¿linked scan¿¿¿, which varies the DIMS compensation voltage and carrier gas helium content simultaneously, was developed. Throughout the linked scan, as the compensation voltage increases, the helium content of the carrier gas is decreased. Thus, the higher mobility ions are transmitted at lower helium content. In this presentation the theory of DIMS linked scans will be discussed. Examples from several applications will be presented.