Determination of tryptamine in rat brain by gas chromatography-mass spectrometry.

Overview

Tryptamine (TA) occurs in trace levels in the brain, but its role in the central nervous system is not clear. However, there is evidence that TA may be a neuromodulator since it binds to specific binding sites in the brain. TA was measured as a diheptafluorobutyryl derivative in rat whole brain by capillary gas chromatography-mass spectrometry using negative chemical ionization (NCI) and single ion monitoring (SIM). d(4)-TA was used as the internal standard. The ions m/z 532 and m/z 536 were monitored to identify TA and d(4)-TA, respectively and to calculate the concentration of TA in rat whole brain which was found to be 0.19 +/- 0.08 ng g(-1) (n = 8). The results confirm the earlier TA concentrations measured by GC-MS using positive electron impact ionization. However, NCI improved the signal/noise ratio of the method increasing its sensitivity for TA.