PREPARING YOUR SAMPLE
  Why does it matter how much sample I have?
Unfortunately, NMR is not a particularly sensitive technique. This means that it is not possible to get an intense signal from a very small sample. In general, you will want to have at least 5 mg in order to run a 1H spectrum; this is the test you will probably run most often. In order to get a 13C spectrum, you should have about 50 mg, so that you get a usable spectrum in a reasonable amount of time. It is possible to record NMR spectra with much less sample, but this may requiree very long experiment runs (up to several days!) and/or special advanced NMR techniques.