4. Acquisition

Time requirement: 10 min Sample: Fill a solid-state rotor with finely powdered glycine.

Load standard ¹³C NMR parameters. Spin the sample at vg = 4 kHz and first run a normal CP/MAS spectrum (see Exp. 14.4). Then load the TOSS pulse sequence. You have to set:

td: 4k sw: 500 ppm o1: middle of C NMR spectrum o2: middle of ¹H NMR spectrum p1: 90° ¹H decoupler pulse p2: ¹H 5 ms spin-lock decoupler pulse p3: ¹³C 5 ms spin-lock transmitter pulse p4: 180° ¹³C transmitter pulse [11 μs] dl:3s d2: 25.2 μs, calculated from (0.1226/ vg) – p4/2 d3: 8.3 μs, calculated from (0.0773/vp) – p4 d4: 44.9 μs, calculated from (0.2236/ vp) – p4 d5: 250 μs, calculated from (1.0433/vp) – p4 d6: 183.2 μs, calculated from (0.7744/ vg) – p4/2 – de decoupler attenuation for cross-polarization decoupler attenuation for high-power cw decoupling, typically 2 dB less than for cross-polarization; on instruments with no fast power switching use same attenuation as for cross-polarization rg: receiver gain for correct ADC input pre-acquisition delay: as short as possible

5. Processing

Use standard 1D processing for C NMR as described in Experiment 3.2 with zero-filling to 4 k and exponential multiplication corresponding to the line-width using |b =

6. Result

The figure shows the spectra of glycine obtained using a multinuclear solid-state probe-head with a 7 mm rotor on an AM-400 spectrometer with wide-bore magnet. The spinning rate was 4000 Hz as seen from the normal CP/MAS spectrum in a, whereas in b the result of the TOSS sequence is given.