Soft Argon-Propane Dielectric Barrier Discharge Ionization.

Area of Science:

• Analytical Chemistry
• Plasma Physics

Background:

• Dielectric barrier discharges (DBDs) are established soft ionization sources for mass spectrometry (MS).
• Helium-based DBDs offer good ionization efficiency and stable plasma but argon-based DBDs require higher voltages and can produce filamentary plasma.
• Argon metastables do not efficiently ionize nitrogen impurities, unlike helium.

Purpose of the Study:

• To develop a homogeneous argon-based dielectric barrier discharge ionization (DBDI) source.
• To reduce ignition and working voltages for argon-based DBDI.
• To improve analyte introduction for nonambient DBDI-MS.

Main Methods:

• Utilized a mixture of argon and propane (C3H8) as an ignition aid for homogeneous plasma generation.
• Introduced analytes into an enclosed system through the discharge capillary.
• Characterized the nonambient DBDI-MS arrangement.

Main Results:

• Propane addition enabled Penning ionization by argon metastables, leading to homogeneous argon-based DBDI.
• Achieved lower ignition and working voltages compared to traditional argon DBDs.
• Demonstrated a novel enclosed system for analyte introduction, enhancing interaction with reactant ions.

Conclusions:

• Homogeneous argon-based DBDI is feasible using propane as an ignition aid.
• The nonambient DBDI-MS setup enhances analyte ionization efficiency.
• This approach paves the way for integrating DBDI with separation techniques like GC and HPLC.