High sensitivity field asymmetric ion mobility spectrometer

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Instrument Development

Background:

• Field Asymmetric Ion Mobility Spectrometry (FAIMS) is a powerful technique for chemical analysis.
• Existing FAIMS systems can be limited by sensitivity and signal-to-noise ratio.
• Advancements in electronics and detection methods are crucial for improving FAIMS performance.

Purpose of the Study:

• To design, fabricate, and test a high-sensitivity FAIMS system.
• To investigate the use of synchronous modulation/demodulation for enhanced signal-to-noise ratio.
• To determine the limit of detection for standard chemical compounds using the developed FAIMS.

Main Methods:

• A FAIMS system was constructed with a 10.6 eV UV photoionization source, a high voltage/high frequency ion filter, and a low noise ion detector.
• The ion filter electronics generated square waveforms up to 1000 V at 1 MHz.
• A synchronous modulation/demodulation technique was implemented, modulating the compensation voltage and demodulating the ion current.

Main Results:

• The FAIMS system demonstrated high sensitivity in detecting standard chemical compounds.
• The synchronous modulation/demodulation technique improved the signal-to-noise ratio.
• An extrapolated limit of detection for acetone was determined to be 10 parts per trillion (ppt) with a 1-second averaging time.

Conclusions:

• The developed high-sensitivity FAIMS system offers enhanced performance for chemical analysis.
• The synchronous modulation/demodulation technique is effective in improving FAIMS measurements, especially at low concentrations.
• The system shows promise for sensitive detection of volatile organic compounds and other analytes.