Quantitative analysis of histamine in biological samples by gas chromatography--mass spectrometry

A mass fragmentographic method for the quantitative analysis of histamine in the supernatant from antigen-challenged leukocytes, whole blood, and urine is described. Histamine labeled with two 15N atoms was synthesized and added to the sample as an internal standard. N alpha-Heptafluorobutyryl-N tau-ethoxycarbonylhistamine was prepared for mass fragmentographic analysis and the molecular ions at m/z 379 and 381 were used for monitoring histamine and 15N2-labeled histamine, respectively. The quantitation limit of histamine was 2 ng by this method. The experimental error of the method was less than 7% at the level of 5 ng in the supernatant from antigen-challenged leukocytes. The value obtained by this method correlated well with that from radioisotopic enzymatic assay (r=0.990).