科研之友
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摘要
RATIONALEWe describe the miniaturization of a linear-type ion trap mass spectrometer for possible applications in portable chemical analysis. This work demonstrates the potential and the advantages of using lithographically patterned electrode plates in realizing an ion trap with dimension y(0) less than 1 mm. The focus of this work was to demonstrate the viability and flexibility of the patterned electrode approach to trap miniaturization, and also to discover potential obstacles to its use. %26lt;br%26gt;METHODSPlanar, low-capacitance ceramic substrates were patterned with metal electrodes using photolithography. Plates that were originally used in a linear trap with a half-spacing (y(0)) of 2.19 mm were positioned much closer together such that y(0) = 0.95 mm. A capacitive voltage divider provided different radiofrequency (RF) amplitudes to each of 10 electrode elements (5 on each side of the ejection slit), and the capacitor values were adjusted to provide the correct electric field at this closer spacing. The length of the trapping region, 45 mm, is unchanged from the previous device. %26lt;br%26gt;RESULTSElectron ionization mass spectra of toluene and dichloromethane demonstrate instrument performance, with better than unit mass resolution for the molecular ion and fragment ion peaks of toluene. Compared with the larger plate spacing, the signal is reduced, corresponding to the reduced trapping capacity of the smaller device. However, the mass resolution of the larger device is retained. %26lt;br%26gt;CONCLUSIONSLithographically patterned substrates are a viable pathway to fabricating highly miniaturized ion traps for mass spectrometry. These results also demonstrate the possibility of significant reduction of the ion trap volume without physical modification of the electrodes. These experiments show promise for further miniaturization using assemblies of patterned ceramic plates.
- 出版日期2014-6-30
