Project

High-Density Cylindrical Ion Trap Array Mass Spectrometer

SRI has developed small, highly sensitive arrays for pervasive monitoring of chemical and biological processes in the ocean and other environments.

Micro-cylindrical ion trap arrays

Among elemental and molecular analysis techniques, mass spectrometry provides the highest sensitivity, specificity, and versatility. It also provides analytical access to elements, isotopes, and complex molecules. A mass spectrometer (MS) is an analytical instrument that measures the mass-to-charge ratio of ions (charged atoms and molecules) to determine their elemental identities or composition.

Mass spectrometry can also be used to elucidate the chemical structure of molecules and determine relative concentrations of chemicals in complex samples. Commercially available MSs, however, are typically large, power-hungry, and expensive instruments.

SRI has created and tested high-density (HD) arrays of micro-cylindrical ion traps (µ-CITs) and will demonstrate their potential use as small, relatively inexpensive, yet highly sensitive MSs. The arrays will be constructed in silicon using microelectromechanical systems (MEMS) processing methods that are amenable to batch fabrication and on-chip integration of electronics.

Large HD µ-CIT MS arrays may have comparable, or possibly superior, sensitivities to commercially available conventional ion trap mass spectrometers because of the integration of signals from the individual µ-CITs. MSs based on this technology will also have lower system power and vacuum requirements, and thus be less expensive to fabricate and operate.

The array’s novel modes of operation also provide unique analytical capabilities, allowing for pervasive networks of highly versatile, sensitive chemical analyzers with a profound impact in marine science and technology, environmental science, and analytical chemistry. For example, networks of µ-CIT based MSs in the ocean could allow pervasive monitoring of a wide range of highly dynamic chemical and biological processes, and serve as an early warning system for events such as blooms of red tide.

This project also included education and outreach at the University of South Florida College of Marine Science’s Oceanography Camp for Girls. During a two-morning laboratory each summer at SRI, selected entering high school freshmen girls learned about mass spectrometry and microfabrication methods through a series of hands-on laboratory experiences and demonstrations.

This effort was based upon work supported by the National Science Foundation under award CHE 0923977.  Any opinions, findings, and conclusion or recommendation expressed in the publication are those of the authors and do not necessarily reflect the views of the National Science Foundation.