1. Purpose

Sensitivity is one of the most debated points between manufacturers and customers buying new NMR instruments. Furthermore, sensitivity plays a central role concerning the performance of an NMR instrument in its everyday use. Therefore, standardized tests have been developed which must be critically and honestly performed to yield meaningful results. In this experiment we describe the standard ¹H sensitivity test using ethyl benzene.

2. Literature

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 proton NMR sequence and phase cycle

4. Acquisition

Time requirement: 10 min

Sample: 0.1% ethyl benzene in CDCl₃, degassed and sealed.

The magnet is shimmed as well as possible (see Ch. 1, Section 1.4). For a meaningful sensitivity test, the line-shape and resolution tests (Exps. 3.5 and 3.6) should be satisfactory. Load standard ¹H NMR parameters. You have to set:

td	32 k
sw	10 ppm