A Novel Microwave-Induced Plasma Ionization Source for Ion Mobility Spectrometry

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Environmental Science

Background:

• Ion mobility spectrometry (IMS) is a powerful technique for analyzing chemical species.
• Conventional ionization sources in IMS can have limitations in sensitivity and performance.
• There is a need for advanced ionization methods to improve IMS capabilities.

Purpose of the Study:

• To introduce and evaluate a novel microwave induced plasma ionization (MIPI) source, Surfatron, for ion mobility spectrometry.
• To assess the performance of the MIPI-IMS for the detection of volatile organic compounds (VOCs).
• To demonstrate the potential of MIPI-IMS in air quality monitoring applications.

Main Methods:

• Development of the Surfatron MIPI source, featuring a copper cavity and hollow quartz discharge tube.
• Ion mobility measurements of synthetic air in both positive and negative ion modes.
• Performance evaluation including reduced mobility, relative standard deviation, total ion current, signal-to-noise ratio (SNR), limit of detection (LOD), and linear range.
• Application of MIPI-IMS for the detection of specific VOCs like methyl tert-butyl ether (MTBE) and triethylamine.

Main Results:

• The MIPI source produced higher total ion current compared to conventional 63Ni sources.
• Reduced mobilities for synthetic air were measured at 2.14 cm2V-1s-1 (positive) and 2.29 cm2V-1s-1 (negative).
• Excellent SNR (110) and a low LOD (14 pptv) were achieved for MTBE.
• A wide linear range (2.5 orders of magnitude) was demonstrated for triethylamine detection.

Conclusions:

• The Surfatron MIPI source is a viable and effective ionization method for IMS.
• MIPI-IMS offers significant improvements in sensitivity and performance over conventional methods.
• This technology holds great potential for sensitive and reliable monitoring of air pollutants.