Ion Mobility Spectrometry – Mass Spectrometry Performance Using Electrodynamic Ion Funnels and Elevated Drift Gas Pressures
The ability of ion mobility spectrometry coupled with mass spectrometry (IMS-MS) to characterize biological mixtures has been illustrated over the past eight years. However, the challenges posed by the extreme complexity of many biological samples have demonstrated the need for higher resolution IMS-MS measurements. We have developed a higher resolution ESI-IMS-TOF MS by utilizing high pressure electrodynamic ion funnels at both ends of the IMS drift cell and operating the drift cell at an elevated pressure compared to a previous design. The ESI-IMS-TOF MS instrument consists of an ESI source, an hourglass ion funnel used for ion accumulation/injection into an 88 cm drift cell followed by a 10 cm ion funnel and a commercial orthogonal time-of-flight mass spectrometer providing high mass measurement accuracy. It was found that the rear (exit) ion funnel could be effectively operated as an extension of the drift cell when the DC fields were matched, allowing the instrument to have an effective drift region of 98 cm. Two differentially pumped quadrupole regions were used to couple the IMS and TOF MS to focus and minimize the ion transient time between the stages. The resolution of the instrument was evaluated at pressures ranging from 4 to12 Torr and ion mobility drift voltages of 16 V/cm (4 Torr) to 43 V/cm (12 Torr). An increase in resolution from 55 to 80 was observed from 4 to 12 Torr nitrogen drift gas with no loss in sensitivity. Given the increased usage of ion funnels prior to ion mobility separations, additional attention was directed towards the influence of drift gas on the observed ion populations trapped and transmitted using an electrodynamic ion funnel. The choice of drift gas was shown to influence the degree of ion heating and relative trapping efficiency within the ion funnel.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 919281
- Report Number(s):
- PNNL-SA-52620; JAMSEF; 400412000; TRN: US200822%%12
- Journal Information:
- Journal of the American Society for Mass Spectrometry, 18(7):1176-1187, Vol. 18, Issue 7; ISSN 1044-0305
- Country of Publication:
- United States
- Language:
- English
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