Miniaturization of mass analyzers has been studied for its implication in fieldable instrumentation. Smaller analyzers yield improvements in power consumption and significantly decreased pumping system and RF voltage requirements, yielding a smaller device and lower power overall. The quadrupole ion trap is ideal for this application due to intrinsically less stringent vacuum requirements and its ability to perform multiple stages of mass spectrometry using a single analyzer. Specifically, the cylindrical ion trap (CIT) and rectilinear ion trap (RIT) geometries are ideal candidates for miniaturization due to their simplified flat electrodes. Novel fabrication methods such as those used for micro-electro-mechanical systems (MEMS) and rapid prototyping techniques, such as stereolithography (SLA), provide the foundation to realize this project. The focus of this effort is the design and implementation of miniature ion traps.
Projects based on MEMS and SLA fabrication methods will be described. First, a massively parallel array of cylindrical ion traps, fabricated using MEMS technology, with dimensions on the order of 1 μm is described. This project follows a revolutionary approach to miniaturization, by drastically shrinking the size of the analyzer with the aim to operate at atmospheric pressure and very low power requirements.
Both miniature single RITs and two dimensional arrays of RITs are also discussed. Fabricated using the SLA method, an iterative design process was followed for a more evolutionary approach to miniaturization. In the course of this study, three traps of different sizes were fabricated, beginning with a "full size" device measuring 10 x 8 x 50 mm. The next two traps were scaled down by a linear factor of one-half and one-third. Also, a circular, two dimensional array of RITs was also fabricated. Figures of merit for these devices are compared.
