Standard ¹³C sensitivity test sample: 10% Ethylbenzene in chloroform-d.

Record a conventional ¹H spectrum.

Record a conventional ¹³C spectrum.

The calibration of the ¹³C sensitivity test is performed using the standard ¹³C parameter set (the pulse program is set to pulprog zgdc). This test is also a very critical test of the decoupler efficiency. 

The sensitivity is measured on the highest line in the aromatic part of the spectrum according to the equation:
 
                                       S/N=2.5*(height of aromatic)/(peak to peak amplitude of noise)

It is very important to use a long recycle delay, usually d1=5*T1(¹³C) (for instance d1=300 s).

Set p1 to the 90º ¹³C observe pulse at high power level pl1. If required, the CPD ¹H pulses from the decoupler should be recalibrated.

See spectrum

. Plot the spectrum from 200 to 0 ppm using a CY of 12 cm for a standard A4 chart paper. Use sufficient vertical amplitude (min. 1.5 cm) to plot the noise between 120 and 80 ppm.