title: A mass-selective variable-temperature drift tube ion mobility-mass spectrometer for temperature dependent ion mobility studies.
abstract: A hybrid ion mobility-mass spectrometer (IM-MS) incorporating a variable-temperature (80-400 K) drift tube is presented. The instrument utilizes an electron ionization (EI) source for fundamental small molecule studies. Ions are transferred to the IM-MS analyzer stages through a quadrupole, which can operate in either broad transmission or mass-selective mode. Ion beam modulation for the ion mobility experiment is accomplished by an electronic shutter gate. The variable-temperature ion mobility spectrometer consists of a 30.2 cm uniform field drift tube enclosed within a thermal envelope. Subambient temperatures down to 80 K are achievable through cryogenic cooling with liquid nitrogen, while elevated temperatures can be accessed through resistive heating of the envelope. Mobility separated ions are mass analyzed by an orthogonal time-of-flight (TOF) mass spectrometer. This report describes the technological considerations for operating the instrument at variable temperature, and preliminary results are presented for IM-MS analysis of several small mass ions. Specifically, mobility separations of benzene fragment ions generated by EI are used to illustrate significantly improved (greater than 50%) ion mobility resolution at low temperatures resulting from decreased diffusional broadening. Preliminary results on the separation of long-lived electronic states of Ti(+) formed by EI of TiCl(4) and hydration reactions of Ti(+) with residual water are presented.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, TX, USA.
authors.forename: Jody C
authors.initials: JC
authors.lastname: May
authors.forename: David H
authors.initials: DH
authors.lastname: Russell
mesh_terms: D001554:Benzene / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D003080:Cold Temperature; D004867:Equipment Design; D007477:Ions / Q000737:chemistry*; D007726:Krypton / Q000737:chemistry; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods; D009584:Nitrogen / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
chemical_list: D002712:Chlorides; D007477:Ions; D007726:Krypton; D014025:Titanium; D001554:Benzene; D009584:Nitrogen