Simultaneous measurement of acetylcholine and choline in brain by pyrolysis-gas chromatography-mass spectrometry.

Pyrolysis-gas chromatography and chemical ionization mass fragmentography were combined to develop a specific, simple and rapid method for simultaneously measuring endogenous and stable isotopic variants of acetylcholine and choline with a detection limit of approximately 10(-12) mol. The recovery and reproducibility of the method are excellent, and the method is suitable for measuring acetylcholine and choline in discrete regions of rat brain and to measure incorporation of choline into acetylcholine, both of which uses are demonstrated. This method affords easy analysis of 40 samples in a working day. The new technique used to extract compounds from tissues and the modified gas flow arrangement may be useful to measure other compounds as well.