I'm trying to set up a vacuum line for evacuating NMR tubes prior to sealing
with a torch. What vacuum pressures are sufficient to remove atmospheric
oxygen from the sample? Also, I'd like to know what various methods are used
to remove oxygen from the sample: I've heard of freeze-dry methods where the
sample in the tube is frozen in liquid nitrogen and the tube is evacuated and
sealed, and also bubbling inert gas (nitrogen and argon) through the
liquid sample prior to sealing. Anybody out there willing to share their
opinions on the efficacy of such methods?
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Edward T. Chainani Nuclear Magnetic Resonance Laboratory Manager
National Chemistry Instrumentation Center (NCIC)
Ateneo de Manila University phone: (632) 924-4601 loc. 2309
Loyola Heights, Quezon City e-mail: etch@ginto.chem.admu.edu.ph
Philippines
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