This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A gate valve was designed to separate the ESI source from the UHV section of the ESI-FTMS instrument. This gate valve was designed to eliminate large field-free regions associated with commercially available gate valves. This design was integrated into the ESI-qQq-FTMS instrument designed in collaboration with MDS Sciex. A titanium hexapole immediately follows Q2 and focuses ions through the home built, minimum thickness gate valve. A second transfer hexapole immediately follows the gate valve and transfers the ions to the ICR cell. This hexapole is split into three sections with 4- and 2-mm stainless steel conductance limits placed after the first and second hexapole segments, respectively. Transmission efficiencies of 95% have been routinely observed. This year, the gate valve was modified to use a commercial linear motion feedthrough rather than an o-ring sealed shaft from the previous design and the upgraded gate valves were installed on both the MALDI and ESI instruments.
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