Dear EPR community,
I'd like to know a reliable method to clean out EPR tubes which previously held a sample in solution, particularly in the case of samples containing transition metal species. I'm sure some solution of EDTA is involved, but I'd like hear your tried and true methods (solution(s) composition, soak time, drying, etc.).
Thanks in advance,
Matt
Do you still see signal after washing the tubes with a pipe cleaner with soap and water? How you wash depends on what contamination you are worried about. My general go to was isopropanol with 10% by volume of conc. HCl solution to get rid of metals in sample tubes if I was really worried about it.
Wilmad has some general instruction on cleaning NMR tubes:
https://www.wilmad-labglass.com/Support/NMR-and-EPR-Technical-Reports/Proper-Cleaning-Procedures-for-NMR-Sample-Tubes/
and they also sell tube washers, listed in the WILMAD NMR Catalog as Solvent Jet Cleaners.
I would also try using acids to convert paramagnetic ions into soluble salts that could be removed with water.
Finally, in old days when we were using a lot of tubes, I would simply buy 3x4 mm clear quartz in 3 -4 ft length from one of the supplier, and then make tubes myself using an oxygen torch (use gas but not hydrogen to decrease background signal and wear a proper eye protection). Plain quartz tube should cost about 0.3-0.4$/ft and with some skills one can make a tube in about a minute. Much easier than washing...
Alex
Thanks Alex; cutting your own tubes certainly makes life easier than washing old ones. I considered using some type of chelating agent to remove any Cu(II) species adsorbed to the tube walls, but of course it is more sensible to use new clean tubes for an experiment.
Best,
Matt
- Badges
- Science topic
- Similar topics
- Methodology
- Laboratory
- Laboratory Techniques