High Resolution Nuclear Magnetic Resonance Spectroscopy High Resolution Nuclear Magnetic Resonance Spectroscopy Introduction Thirty years ago was very difficult to manufacture powerful magnets magnets which could produce suitably uniform magnetic fields. These instruments operated at 30 MHz or 40 MHz. Technology has now progressed and much more powerful, effective magnets are available.
Higher frequencies give rise to higher resolution.
That is to say high resolution instruments are able to separate or resolve peaks which are close together. Using this type of spectrometer it is found that some absorptions which appeared to be single peaks using older instruments, actually consisted of several peaks close together. This phenomenon is known as spin-spin coupling . However not only does the effective field depend upon the effect of moving electrons in the local environment, it also depends upon the nuclei of other hydrogen atoms in the vicinity. The hydrogen atoms of the methyl group are adjacent to two other hydrogen atoms of the methylene group.