Selected-ion monitoring gas chromatographic-mass spectrometric analysis of catecholamines: enhancement of sensitivity by a simple clean-up step on Sephadex G-10.

The sensitivity of catecholamines using selected-ion monitoring gas chromatography-mass spectrometry (SIM GC-MS) has been enhanced by employing a simple clean-up step using Sephadex G-10 columns. This procedure allows for the detection of extremely small amounts (1-10 pg) of biogenic amines (e.g., epinine) which corresponds to a 25-fold increase in detection limits compared to electron ionization GC-MS or high-performance liquid chromatography with electrochemical detection (HPLC-ED). The SIM GC-MS assay was used to monitor the dopamine-beta-hydroxylase-mediated conversion of epinine d6 to epinephrine d6 in rat hypothalamus and brainstem in vitro and the results were compared to those obtained by HPLC-ED.