Hair is not a particularly simple matrix to work with.
Once it has been digested there are so many compounds present that only Gas Chromatography Mass Spectrometry (GC-MS) or Liquid Chromatography (LC)-MS is sufficiently selective and sensitive to detect a single compound.
If you are using a mass selective detector then deuterated analogues are without doubt the best internal standard to use as a one point calibration is sufficient.
GC-FID (Flame Ionising Detector) or NPD (Nitrogen - Phosphorus detector) or even LC-DAD (diode array detector) produce too much noise when analysing hair so are not viable techniques, in my experience.
There are no commercially available molecularly imprinted polymers, that I know of, for selective separation of nicotine from complex matrices and even if there were these are not great for analysis of drugs in hair.