Isolation, separation and analysis in neurochemistry: trace amines and acids as an illustrative example.
In this brief overview various neurochemical isolation procedures that can be adopted for the analysis of several monoamine neurotransmitters/neuromodulators and their principal oxidatively deaminated metabolites are outlined. With respect to the trace amines, they can be identified and quantitated as their so-called dansyl derivatives after thin-layer chromatographic separation by mass spectrometric (MS) electron-impact (EI) ionisation followed by selected-ion monitoring (SIM) of their molecular ions. Deuterated homologues are added as internal standards at the start of the analytical procedure. The MS-EI-SIM procedure offers a tissue extract or releasate sensitivity of about 100 pg/g of tissue or fluid. In the case of tryptamine or phenylethylamine, by utilising different derivatives (N-acetylpentafluoropropionyl or N-acetylpentafluorobenzoyl), which cyclise to form perfluorinated spirocyclic compounds, it is possible using MS negative chemical ionisation techniques coupled with monitoring of the (M-HF) ions to achieve sensitivities for tissue extracts of 1 pg/g or less. Acidic and neutral metabolites (up to twelve of them can be assayed simultaneously) can be detected and quantitated in tissue extracts, releasates or biological fluids as their methylpentafluoropropionyl or trifluoroethyl-pentafluoropropionyl derivatives in the 100-1000 pg range using gas chromatographic-MS-SIM procedures.
Boulton
A A
AA
Neuropsychiatric Research Unit, University of Saskatchewan, Saskatoon, Canada.
Durden
D A
DA
Davis
B A
BA
D000588:Amines / Q000032:analysis / Q000302:isolation & purification*; D004586:Electrophoresis; D008401:Gas Chromatography-Mass Spectrometry; D013058:Mass Spectrometry; D018377:Neurotransmitter Agents / Q000032:analysis / Q000302:isolation & purification*
D000588:Amines; D018377:Neurotransmitter Agents