NMR tube

In particular, an NMR tube which has poor camber may wobble when rotated, giving rise to spinning side bands.

With modern manufacturing techniques even cheap tubes give good spectra for routine applications.

Sonication and scrubbing with a pipe cleaner may be helpful in removing traces of solid contaminants.

Care should be taken with these solutions, as they can unexpectedly and violently erupt from the NMR tube due to pressure build-up (aqua regia) or explosion (piranha).

Chromic acid solutions are never used, due to traces of paramagnetic chromium left behind on the tubes causing interference with NMR experiments.

[4] When the NMR tube is determined to be clean, it is triple-rinsed with distilled water and left to air-dry or dry in an oven at low temperature.

[5] If NMR tubes are washed, a final rinse is recommended with a solvent that easily evaporates at 60 °C and that has no residue such as methanol.

It is an apparatus which uses a vacuum to flush solvent and/or a detergent solution through the entire length of the NMR tube.

Note to complete the vacuum a flask is attached to the NMR tube cleaning apparatus.

This sort of apparatus is commercially available,[6] though it is costly and easy to destroy by shattering or breaking off the cleaning tube.