主题:【讨论】1H-NMR定量问题

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danding_danding
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请问:氢谱定量实验,系统适应性实验和方法学验证都需要做些什么?
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sslin
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定量实验可以考虑使用内标 (例如环几烷或二氧六环), 或制作标准工作曲线, 利用内插或外插法进行定量计算.
celan
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原文由 danding_danding(danding_danding) 发表:
请问:氢谱定量实验,系统适应性实验和方法学验证都需要做些什么?


[list=disc]
  • Good signal to noise
  • 90° pulse sufficiently short to excite the entire region uniformly
  • Delay between pulses of at least 5 T1’s
  • Flat base line to start with and baseline correction
  • 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 [list=circle]
  • 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
  • celan
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    原文由 sslin(sslin) 发表:
    定量实验可以考虑使用内标 (例如环几烷或二氧六环), 或制作标准工作曲线, 利用内插或外插法进行定量计算.


    做定量1HNMR,内标物的选择还是有讲究的,要求内标物纯度要好,内标物与样品的被积分信号应有好的分离(否则不利积分)。。。。
    环己烷和二氧六环并不是好的内标物质(暂且不讨论其信号是不是与被测物质的信号有好的分离),环己烷是低沸点的(约80摄氏度)易挥发,不易准确称量。二氧六环虽然沸点较高,但容易吸水,对准确称量也不利。
    aspect
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    zhongguyan
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    Utopia
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    可考虑用联苯或萘或它们的单烷基取代衍生物,固体,好称量
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