Solid State NMR: Observe C13 with high power H1 and F19 decoupling

(This file has been upload to web notes also there is a hardcopy in EXP. section of file cabinet)

Hardware Requirement:

HFX probe

1. F19 pass, H1 stop filters; H1 pass F19 stop filter and one combiner
2. 1Kw LB amplifier, 1Kw H/F amplifier, 300W or 500 W H/F amplifier

Setup Procedure:

Install the probe.

1. It is a wide board probe, use WB accessories. And Air support connections.
2. Connect probe as following:

CH1: C13 -- LB 1Kw -- Pre Amp -- LB pass filter -- direction coupler à probe X channel

CH2: H1 -- HB 1Kw -- by pass pre Amp -- H1 pass filters -- combiner à probe H channel

CH3 F19 -- HB 300W -- by pass pre amp -- F19 pass filter -- combiner à probe H channel

Note:

We could check the pulse sequence by connect the scope the output from the sequence generator or before the input to the amplifiers (at the front of the amplifiers). These outputs are low power (under 1 volt).

Double check if the sequence is correct before connect to the amplifiers input.

When decoupling H1 and F19, Use spinal decoupling sequence, the probe will arc (even H1 at -0.8dB). But both of them use cw decoupling, then it is OK up to H1 (-2 dB) F19 (5dB).

Need more research on this part? When use H1 spinal decoupling only, the line width is 448Hz. H1 cw decoupling only, 1173 Hz. H1 and F19 CW decoupling, 291 Hz.

1. Tune the probe on Adamantane ------- If shim and C13 calibration is necessary. Otherwise tune on the CH2F-COCOOLi standard sample.

Final Tune Setup:

Use /u/exp/stan/nmr/lists/pp/1H19F13Ctune.av.akm to start.

Use /u/exp/stan/nmr/lists/pp/coechoadcaq32.av.akm for final check

C13 PL1 -2 db forward 970mv (with all attenuator in place 40 dB + 10 dB)

Reflect 43 mv or less

H1 PL12 -0.8 forward 432 mv

Reflect 66mv

F19 PL3 5db forward 292

Reflect 46 mv

1. Fine Tune and Parameters for the Standard Sample:

Standard Samples for calibration:

10:1 C1-C13, N15 - Ala + 10% of Admantane.

F19 sample:

FCH2-COCOOLi Fluropyrorate Li salt