核磁共振 定量_nmr_实验条件要注意的问题和应用领域

 核磁共振定量NMR 实验

  实验考虑:

  Good signal to noise 好的信燥比

  90° pulse sufficiently short to excite the entire region uniformly

  Delay between pulses of at least 5 T1’s 脉冲延迟至少T1的5倍

  Flat base line to start with and baseline correction 基线平坦和基线校正

  Filter bandwidth set to at least twice the sw

  Enough data points to give 15 to 20 points per peak - remember that you lose half the points to the imaginaries in Fourier transformation

  Acquire at least 32k and zero fill several times – memory is cheap

  Exception to 32k for other nuclei requiring 1H decoupling - it is important to limit the acquisition time to as short as possible to avoid NOE build up during the acquisition so < 32k may be necessary with zero filling to make up the difference

  Zero filling should only be done after dc correction and line broadening otherwise it introduces baseline artifacts

  Gated decoupling for non-hydrogen analysis

  Careful phasing on a spectrum that has been greatly expanded in the vertical direction

  Careful integration

  Place a single integral over the spectral limits of interest

  Adjust bias and slope on the full integral

  Cut integral into smaller regions as close as possible to the peak

  Consistently include or exclude satellites or account for them when they overlap



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