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Hi I am working on a Varian 500MHz NMR. I am attempting to use the pulse sequence satxfer1D to measure the rate constant of an exchanging system. I am not using solvent suppression and I am having trouble understanding the physics behind the "mixing time" after the 90 pulse. I also do not know how many iterations the selective pulse should go through because it seems that if I turn the mixing time off and just use a selective pulse, and then a pw90, I will still obtain the same spectrum no matter how many iterations the selective pulse train goes through. Does anyone have any thoughts/ideas? |
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The mixing time is a T1 rho filter to reduce the protein background signal and should have little effect on the STD signal. The filter works well for larger proteins, but may have to be increased for smaller proteins. We typically use the default settings for the saturation pulse train, see the original Mayer & Meyer article (JACS, 2001, 123, 6108-6117) for more details on this. We also select satmode='ny' and depend only on the DPFGSE sequence for water suppression. Finally, we have found that the experiment works best in D2O. |
