Microfabrication of cylindrical ion trap mass spectrometer arrays for handheld chemical analyzers (original) (raw)
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Journal of the American Society for Mass Spectrometry, 2017
We present a new two-plate linear ion trap mass spectrometer that overcomes both performance-based and miniaturization-related issues with prior designs. Borosilicate glass substrates are patterned with aluminum electrodes on one side and wire-bonded to printed circuit boards. Ions are trapped in the space between two such plates. Tapered ejection slits in each glass plate eliminate issues with charge build-up within the ejection slit and with blocking of ions that are ejected at off-nominal angles. The tapered slit allows miniaturization of the trap features (electrode size, slit width) needed for further reduction of trap size while allowing the use of substrates that are still thick enough to provide ruggedness during handling, assembly, and in-field applications. Plate spacing was optimized during operation using a motorized translation stage. A scan rate of 2300 Th/s with a sample mixture of toluene and deuterated toluene (D8) and xylenes (a mixture of o-, m-, p-) showed narrow...
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Review of Scientific Instruments, 2007
A description of the design and microfabrication of arrays of micrometer-scale cylindrical ion traps is offered. Electrical characterization and initial ion trapping experiments with a massively parallel array of 5 m internal radius ͑r 0 ͒ sized cylindrical ion traps ͑CITs͒ are also described. The ion trap, materials, and design are presented and shown to be critical in achieving minimal trapping potential while maintaining minimal power consumption. The ion traps, fabricated with metal electrodes, have inner radii of 1, 2, 5, and 10 m and range from 5 to 24 m in height. The electrical characteristics of packaged ion trap arrays were measured with a vector network analyzer. The testing focused on trapping toluene ͑C 7 H 8 ͒, mass 91, 92, or 93 amu, in the 5 m sized CITs. Ions were formed via electron impact ionization and were ejected by turning off the rf voltage applied to the ring electrode; a current signal was collected at this time. Optimum ionization and trapping conditions, such as a sufficient pseudopotential well and high ionization to ion loss rate ratio ͑as determined by simulation͒, proved to be difficult to establish due to the high device capacitance and the presence of exposed dielectric material in the trapping region. However, evidence was obtained suggesting the trapping of ions in 1%-15% of the traps in the array. These first tests on micrometer-scale CITs indicated the necessary materials and device design modifications for realizing ultrasmall and low power ion traps.
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With the increasing application field, a higher requirement is put forward for the mass spectrometer. The reduction in size will inevitably cause a loss of precision; therefore, it is necessary to develop a high-performance miniature mass spectrometer. Based on the researches of rectangular ion trap, the relationship between mass resolution and structural parameters of the ion trap array was analyzed by further simulation. The results indicate that, considering the balance of mass resolution and extraction efficiency, the preferable values for the field radius of exit direction y0 and ion exit slot width s0 are 1.61 mm and 200 μm, respectively. Afterwards, a miniature four-channel ion trap array (MFITA) was fabricated, by using MEMS and laser etching technology, and mass spectrometry experiments were carried out to demonstrate its performance. The mass resolution of butyl diacetate with m/z = 230 can reach 324. In addition, the consistency of four channels is verified within the err...
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Journal of Microelectronics and Electronic Packaging, 2016
The current computing power and network capabilities of handheld smart devices is helping to drive the development of new sensors, enabling the Internet of things. A chip-based mass spectrometer technology promises to offer a smart-device autonomous microsystem chemical analysis capability for sample determination and process monitoring for multiple applications in a small low-power instrument package. This project focuses on the development of cylindrical ion trap (CIT) mass analyzer chips fabricated using three-dimensional (3-D) additive manufacturing (AM) and planar low temperature cofired ceramic thick film processes for a chip-based mass spectrometer microsystem. The CIT is a mass analyzer composed of planar electrodes and operates by trapping and ejecting sample ions based on their mass in a radiofrequency field. Because of its simplicity, CITs may be easily miniaturized and connected in tandem to achieve multiplexing. AM materials and methods enable enhanced trap miniaturizat...
International Journal of Mass Spectrometry, 2006
A novel technique for the fabrication of miniature cylindrical ion trap (CIT) mass spectrometers using a non-conductive substrate has been developed. This technique demonstrated the feasibility of batch fabricating accurate and low-cost CITs. A CIT ring electrode (r 0 = 1.375 mm) was fabricated using multiple layers of low temperature co-fired ceramics (LTCC) which were punched and then compressed in a ring-electrode die. Uniform compression was achieved, and cracking avoided, by tailoring the thickness of the LTCC stack. The stack was then fired at 850 • C to convert the LTCC into a ceramic ring. Areas to be metallized were patterned photolithographically after the ring was subjected to electroless plating. Stainless steel endplates were affixed to the ring electrode to complete the CIT. The prototype CIT was tested in the mass selective instability mode without axial modulation and produced mass spectra with a typical peak width of 1.8 m/z. Simulations of operation were also performed in ITSIM 5.0 after SIMION 7.0 was used to calculate the contribution of higher order multipoles to the nominally quadrupole potential inside the CIT.