Set up of ¹⁹F NMR on DPX300

1. General

Fluorine is in frequency close to the proton (288 MHz at on the ¹H frequency of 300 MHz). The heteronuclear channel of the broadband probe can not be tuned to such a high frequency and observation of Fluorine has to be performed using the proton channel. Therefore proton decoupling is not possible. Sine the setup using the standard BBO probe head requires changing several cables and involves extensive tuning of the proton channel it should only be attempted by experienced users.

2. Procedure

• Create a new dataset with new and call up the fluorine parameter: rpar f19.hf all
  
  
• On the preamplifier disconnect the X-channel cable (middle position) including the Low pass X-filter (0 - P31 pass, H-1 reject). Remove the proton cable from the top position and attach it to the middle position. The broadband preamplifier is now connected to the proton channel of the probe.
  
  
• Enter the acquisition window and type wobb.
  
  
• Adjust the proton channel tuning and match to get the dip centered (and the tuning and matching displays into the green region). Initially there will be no dip visible and turning the screws may have no apparent effect. It is best to start turning the matching screw by one turn and turn the tuning screw through the entire range. Repeat this procedure until you see a change, then alternate between tuning and matching to minimize the deviation.
  
  
• Set up parameters (sw, o1p etc.), and type rga, then zg.
  
  
• When finished ,switch back to regular setup: Connect proton cable to proton cannel and X-cable to X-channel of preamplifier with lowpass filter back in place. Call up a proton data set and type wobb, retune to proton.