Mass Spectroscopy


Mass spectrometry is a method to analyze the composition of a sample. Typically, a sample is ionized and subjected to an electric or magnetic field in order to separate the ions based on their mass-to-charge ratio. One possible technique of mass spectrometry is the use of an ion trap. The ion trap creates an electric field to trap ions, then changes the electric field in order to eject the ions based on their mass-to-charge ratio. In collaboration with Dr. Daniel Austin and the BYU Chemistry Department we are working to microfabricate planar ion trap devices. These devices can be miniaturized and operated at higher pressures compared to other mass analysis techniques. This allows the devices to become more portable, allowing researchers to analyze their samples in the field rather than shipping them back to a lab. Figure 1 shows an example of one of the ion traps built on a ceramic substrate. On the left is the trapping side. The right shows the contact pads for applying the voltage to the trap.

Figure 1 - Ion trap. Left: Trapping side. Right: Voltage side


The left side of Figure 2 shows an illustration of ions trapped in the ion trap. The right side of Figure 2 shows two plates that are put together and spaced with sapphire balls to form the ion trap. Printed circuit boards with capacitor networks are used to create the desired field and pogo pins are used to make contact with the voltage side of the plate.

Figure 2 - Left: Illustration of ions trapped in the ion trap.

 Figure 2 - Right: Assembled ion trap


Figure 3 shows a mass spectra of dichloromethane obtained using traps that were fabricated for the project. Each of the peaks corresponds to a different ion fragment or isotope of the sample. This unique signature can be used to identify the compound.

Figure 3 - Mass spectrum of dichloromethane

Publications

  1. " A Lithographically Patterned Discrete Planar Electrode Linear Ion Trap", Brett J. Hansen, Richard J. Niemi, Aaron R. Hawkins, Stephen A. Lammert, and Daniel E. Austin, IEEE/ASME Journal of Microelectromechanical Systems, PP(99), 1, (2013).
  2. "Coaxial Ion Trap Mass Spectrometer: Concentric Toroidal and Quadrupolar Trapping Regions", Ying Peng, Brett J. Hansen, Hannah Quist, Zhiping Zhang, Miao Wang, Aaron R. Hawkins, and Daniel E. Austin, Analytical Chemistry 83, 5578-5584, (2011).
  3. "Performance of a Halo Ion Trap Mass Analyzer with Exit Slits for Axial Ejection", Miao Wang, Hannah E. Quist, Brett J. Hansen, Ying Peng, Zhiping Zhang, Aaron R. Hawkins, Alan L. Rockwood, Daniel E. Austin, Milton L. Lee, Journal of the American Society for Mass Spectrometry 22, 369-378, (2011).
  4. "Effects of Higher-order Multipoles on the Performance of a Quadrupole Ion Trap Mass Analyzer", Zhiping Zhang, Ying Peng, Hannah Quist, Brett J. Hansen, Aaron R. Hawkins, Daniel E. Austin, International Journal of Mass Spectrometry 229, 151-157, (2011).
  5. "Paul Trap Mass Analyzer Consisting of Opposing Microfabricated Electrode Plates", Zhiping Zhang, Ying Peng, Brett J. Hansen, Ivan W. Miller, Miao Wang, Milton L. Lee, Aaron R. Hawkins and Daniel E. Austin, Analytical Chemistry 81, 5241-5248, (2009).

Supported By: