Proton nuclear magnetic resonance spectroscopy has proven to be an invaluable aid to the organic chemist for identifying unknown compounds. However, the method suffers from relatively poor sensitivity. This limitation is particularly aggravating to researchers involved with natural product isolation and small scale synthetic work. The amount of sample available is frequently less than the 3–5 mg which are normally required to obtain a reasonably good spectrum with a standard 5 mm sample tube. Furthermore, if the sample is purified by gas chromatography, the time required to collect a sufficieptly large sample can run into several hours, or even days. The need for a routine method of handling these microsamples has prompted us to explore sensitivity enhancement methods in our NMR service laboratory.
KeywordsNuclear Magnetic Resonance Capillary Tube Outer Tube Radioactive Contamination Deuterated Chloroform
Unable to display preview. Download preview PDF.
- 1.R. R. Ernst, Advan. Magnetic Resonance 2, 1 (1966).Google Scholar
- 2.D. J. Frost, G. E. Hall, M. J. Green, and J. B. Leane, Chem. Ind. (London) 116 (1967).Google Scholar
- 4.R. E. Lundin, private communication, 1966.Google Scholar
- 8.P. Higham and R. E. Richards, Proc. Chem. Soc. 128 (1959).Google Scholar
- 9.NMR Specialities, Inc., New Kensington, Pa.Google Scholar
- 10.Wilmad Glass Co., Inc., Buena, N. J.Google Scholar
- 11.Kontes Glass Co., Vineland, N. J.Google Scholar