We have been handling milligram samples for nuclear magnetic resonance (NMR) spectroscopy in a capillary with a technique that was developed mainly with gas–liquid chromatography (GLC) collection in mind; however, this technique can also be applied when the sample capillary is filled by a syringe or capillary action. The technique compares favorably with similar ones reported, and combines the following advantages: (1) There is greater flexibility as to the amount of sample collected by GLC. (2) No transfer of the sample from the GLC collection tube to the NMR tube is necessary. (3) Filling and positioning of the collection tube in the probe is less cumbersome than with other microcells. (4) All components are commercially available at low cost and can be assembled quickly.
David W. Mastbrook and Edward P. Ragelis, "An Improved Technique for Handling Milligram Samples for Nuclear Magnetic Resonance Analysis," Appl. Spectrosc. 23, 376-377 (1969)