Analysis of N-alpha-methylhistamine by gas chromatography-mass spectrometry

A gas chromatography-electron capture mass spectrometry assay has been deve loped for the histamine H-3 receptor agonist, N-alpha-methylhistamine (N-al pha-MH). The assay is linear from 50 pg-10 ng, with a limit of detection of 50 pg/ml for gastric juice and plasma, and 50 pg/sample for bacteria (10(7 )-10(8) CFU) and gastric tissue (5-10 mg wet weight), The Limits of quantif ication are 100 pg/ml for gastric juice (%RSD = 1.4) and plasma (%RSD = 9.4 ), and 100 pg/sample for bacteria (%RSD = 3.9) and tissue (%RSD = 5.8). N-a lpha-MH was not present in human plasma, but low levels (1.4 ng/ml and 0.4 ng/ml) were detected in two samples of human gastric juice obtained from pa tients infected with Helicobacter pylori. (C) 2000 Elsevier Science B.V. Al l rights reserved.