title: The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry.
abstract: We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration. Graphical Abstract ᅟ.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA.
authors.forename: Wade C
authors.initials: WC
authors.lastname: Ellis
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA.
authors.forename: Charlotte R
authors.initials: CR
authors.lastname: Lewis
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA.
authors.forename: Anna P
authors.initials: AP
authors.lastname: Openshaw
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA. paul_farnsworth@byu.edu.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Farnsworth
keywords: Ambient desorption/ionization; Dielectric barrier discharge; Hydrogen addition