Basic Information

Abstract Number: 620 - 4
Author Name: Daniel Austin - Brigham Young University
Session Title: Miniature Mass Spectrometers: Reaching the Exponential of the Growth Curve
Event Type: Symposia
Event Title: Converging Ion Traps for Miniaturized Mass Spectrometers

Presider Name:R Graham Cooks
Affiliation:Purdue University

Date: Monday, March 18, 2013
Start Time: 03:15 PM (Slot #4)
Location: 201A

Abstract Content

Two elements have been common to most efforts to miniaturize ion trap mass analyzers: simplification of electrode geometry and the use of either arrays or traps with extended trapping dimensions. Simplification of electrode geometry allows ion traps to be miniaturized without tolerance complications associated with machining hyperbolic surfaces. Cylindrical and rectilinear ion traps exemplify this process: each uses electrodes that are geometrically simpler than those used in the quadrupole and linear ion traps, respectively. Extended trapping dimensions, such as those in linear and toroidal ion traps, allow more ions to be analyzed per scan, offsetting the decreased ion numbers that can be trapped as device dimensions are reduced. We have developed a toroidal ion trap made using cylindrical electrodes, thereby combining both simplified electrode geometry and extended trapping dimensions. In addition, ions ejected from a large area converge to a single point for easier detection. A full-sized version (r[sub]0[/sub] = 6 mm) of this simplified toroidal ion trap shows performance that exceeds that of other published toroidal ion traps. Under current development are two miniaturized versions of this device (r[sub]0[/sub] = 1 and 2 mm), in which the RF and AC electrodes are made using sheets of stainless steel cut using wire EDM. This approach greatly reduces machining costs, and also allows uniformity of trapping dimensions along the toroidal trapping region. Because the major toroidal radius is unchanged from the full-size version, the trapping capacity is not significantly reduced in these miniaturized versions. In addition, an ion guide is integrated on the trap, forming a "[Rho]" shape, to facilitate introduction of ions into the trap. Simulations show that this eliminates the RF barrier for ion introduction.