Design, Fabrication and Mass-spectrometric Studies of a Micro Ion Source for High-Field Asymmetric Waveform Ion Mobility Spectrometry.

Li Li,Chen Chen,Guo Guo,Zeng Zeng,Yun Yun,Jiang Jiang,Du Du

doi:10.3390/mi10050286

Abstract

A needle-to-cylinder electrode, adopted as an ion source for high-field asymmetric ion mobility spectrometry (FAIMS), is designed and fabricated by lithographie, galvanoformung and abformung (LIGA) technology. The needle, with a tip diameter of 20 μm and thickness of 20 μm, and a cylinder, with a diameter of 400 μm, were connected to the negative high voltage and ground, respectively. A negative corona and glow discharge were realized. For acetone with a density of 99.7 ppm, ethanol with a density of 300 ppm, and acetic ether with a density of 99.3 ppm, the sample gas was ionized by the needle-to-cylinder chip and the ions were detected by an LTQ XL™ (Thermo Scientific Corp.) mass spectrometer. The mass spectra show that the ions are mainly the protonated monomer, the proton bound dimer, and an ion-H2O molecule cluster. In tandem with a FAIMS system, the FAIMS spectra show that the resolving power increases with an increase in the RF voltage. The obtained experimental results showed that the micro needle-to-cylinder chip may serve as a miniature, low cost and non-radioactive ion source for FAIMS.

Highlights

In recent decades, chemical sample separation technology, based on the nonlinear characteristic of ion mobility at high and low electric field strengths, has developed rapidly
Chemical sample separation technology, based on the nonlinear characteristic of ion mobility at high and low electric field strengths, has developed rapidly. This technology is known as high-field asymmetric waveform ion mobility spectrometry (FAIMS) [1,2]
We report on the integration of a microelectromechanical systems (MEMS) ion source within planar FAIMS

Summary

Introduction

Chemical sample separation technology, based on the nonlinear characteristic of ion mobility at high and low electric field strengths, has developed rapidly. This technology is known as high-field asymmetric waveform ion mobility spectrometry (FAIMS) [1,2]. Compared with ion mobility spectrometry (IMS) and mass spectrometry (MS), FAIMS is better able to separate the isomers by using the characteristic that ion mobility would be changing at high electric fields (>10 kV/cm). The requirements of the FAIMS as the ion source are the following: high ionization efficiency, low electromagnetic radiation, miniaturization, etc. Several ion sources have been used in the FAIMS

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Results

Conclusion