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Project Abstract |
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| Fig. 1. Example of a 3 element array of Rectangular Ion Traps as employed in a Miniature Mass Spectrometer System. Only the traps and detector - components internal to the vacuum system - are shown in this photograph. |
Since their conception in the early 1950’s[1] and commercial introduction in the 1980’s[2] ion traps have become one of the standard methods in chemical identification. Ion trap based mass spectrometers have the benefit of adequate mass range, small size, speed of analysis, and mass spectral resolution for high surety. They are also easily coupled with other mass analyzers in hybrid devices and, most significantly, have tandem mass spectrometry (MS/MS) capabilities[3, 4] for the direct analysis of complex mixtures. Limited access to the expensive commercial instruments has limited the societal impact of these devices. However, this might be changing as this traditionally lab-confined instrument is becoming the subject of miniaturization, which has spurred a new interest in novel manufacturing methods and integration techniques[5, 6]. This research is demonstrating the impact of progressively smaller ion traps and arrays of ion traps, the latter providing possibilities for examining multiple samples simultaneously and hence increasing throughput. A simple array is shown in Fig. 1. To create the smaller ion trap structures that are needed to reduce (quadratic with size)[7] the power requirements of the system, specifically the RF drive power[8] we use laser-based lithography as a means of reducing the size of the ion trap and creating a monolithic array of individual ion traps[9].
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| Fig. 2. CAD model and constructed monolithic ion trap array (12 ion traps). The board is a standard circuit board material which is not built in the SLA but inserted. |
In addition to the novel manufacturing aspect the smaller ion traps benefit from a smaller volume, maximum operating potential, and reduced power consumption [8, 10]. The compromise between benefits of miniaturization and mass spectrum resolution can now be studied through the use of these mini ion trap arrays in miniature hand held Mass Spectrometer instruments. This graduate research was used as a basis to work with a team of undergraduate students through the Purdue EPICS program to bring sensor technologies into broader use within the community. |
| Papers Generated: |
- M. Yu, M. Fico, S. Kothari, Z. Ouyang and W. Chappell, "Polymer-Based Ion Trap Chemical Sensor", IEEE Sensors J., vol. 6, no. 6, pp. 1429 - 1434, Dec. 2006.
- G. Wu, R. G. Cooks, Z. Ouyang,M. Yu, W. Chappell, and W. Plass,"Ion Trajectory Simulation for Electrode Configurations with Arbitrary Geometries", J Am. Soc. Mass Spectrom., 17(9) pp. 1216-1228, Sept. 2006
- Ouyang, Z., Gao, L., Fico, M., Chappell, W. J., Noll, R. J., Cooks, R. G., “Quadrupole Ion Traps and Trap Arrays: Geometry, Material, Scale, Performance”, European Journal of Mass Spectrometry, 13, pp.13-18, 2007
- Miriam Fico, Meng Yu, Zheng Ouyang, R. Graham Cooks, William J. Chappell, "Miniaturization and Geometry Optimization of a Polymer-Based Rectilinear Ion Trap", Analytical Chemistry, 2007 79, 8076-8082
- Wei Xu, W.J. Chappell, R.G. Cooks, Z.Ouyang, Characterization of electrode surface roughness and its impact on ion trap mass analysis. Journal of Mass Spectrometry, accepted 2008
- Wei Xu, Miriam Fico, Meng Yu, Zheng Ouyang, Graham Cooks, and William Chappell, “On the Use of Full Wave Electromagnetic Solvers for Multi-physics Simulations of Ion Trap Chemical Sensing” submitted to IEEE Antennas and Propagation Transactions
- M. Fico, J.D. Maas, S.A. Smith, Z. Ouyang, W.J. Chappell, and R.G. Cooks, “Circular Arrays of Polymer-based Miniature Rectilinear Ion Traps” submitted to The Analyst
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| Cited References: |
1. Paul, W. and H. Steinwedel, Ein Neues Massenspektrometer Ohne Magnetfeld. Zeitschrift für Naturforschung, 1953. 8: p. 448–450. |
2. Stafford, G.C., et al., Recent improvements in and analytical applications of advanced ion trap technology. International Journal of Mass Spectrometry and Ion Processes, 1984. 60(1): p. 85-98. |
3. Makarov, A., et al., Performance Evaluation of a Hybrid Linear Ion Trap/Orbitrap Mass Spectrometer. Analytical Chemistry, 2006. 78(7): p. 2113-2120. |
4. Xia, Y., B.A. Thomson, and S.A. McLuckey, Bidirectional Ion Transfer between Quadrupole Arrays: MSn Ion/Ion Reaction Experiments on a Quadrupole/Time-of-Flight Tandem Mass Spectrometer. Analytical Chemistry, 2007. 79(21): p. 8199-8206. |
5. Blain, M.G., et al., Towards the hand-held mass spectrometer: design considerations, simulation, and fabrication of micrometer-scaled cylindrical ion traps. International Journal of Mass Spectrometry, 2004. 236(1-3): p. 91-104. |
6. Chaudhary, A., et al., Fabrication and testing of a miniature cylindrical ion trap mass spectrometer constructed from low temperature co-fired ceramics. International Journal of Mass Spectrometry, 2006. 251(1): p. 32-39. |
7. March, R.E. and J.F.J. Todd, Practical Aspects of Ion Trap Mass Spectrometry. Fundamentals of Ion Trap Mass Spectrometry, ed. R.E. March and J.F.J. Todd. Vol. 1. 1995, Boca Raton: CRC Press LLC. 430. |
8. Meng, Y., et al., Polymer-Based Ion Trap Chemical Sensor. Sensors Journal, IEEE, 2006. 6(6): p. 1429-1434. |
9. Fico, M., et al., Circular Arrays of Polymer-based Miniature Rectilinear Ion Traps. Submitted to Analyst, 2008. |
10. Fico, M., et al., Miniaturization and Geometry Optimization of a Polymer-Based Rectilinear Ion Trap. Analytical Chemistry, 2007. 79(21): p. 8076-8082. |
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