1. Purpose

Good ¹³C sensitivity is one of the most important points concerning the performance of any routine NMR service instrument in its everyday use. Therefore, standardized tests have been developed which must be very critically and honestly performed to yield meaningful results. For ¹³C two different tests are in common use. The ASTM (American Society for Testing and Materials) procedure using [D₆]benzene in dioxane described here checks only the ¹³C performance on the observe channel, whereas the sensitivity test with ethyl benzene (Exp. 3.10) also tests the ¹H decoupling efficiency at the same time.

2. Literature

Standard Practice for Data Presentation Relating to High Resolution NMR Spectroscopy, American Society for Testing and Materials, Designation E 386-90, Annual Book of ASTM Standards, Philadelphia, 1990; reprinted in: H. Günther, NMR Spectroscopy, 2nd Edition, Wiley, Chichester, 1995.
T. D. W. Claridge, High-Resolution NMR Techniques in Organic Chemistry, Pergamon, Oxford, 1999, 107–108.
C. Anklin, D. v. Ow, H. Ruegger, Standard Test Procedures for Supercon Systems, Spectrospin AG, Fällanden, 1988.

3. Pulse Scheme and Phase Cycle

Single-pulse carbon-13 acquisition for the ASTM sensitivity test

4. Acquisition

Time requirement: 10 min

Sample: 60% [D₆]benzene in 1,4-dioxane, degassed and sealed.