Interference with the Fluorometric Histamine Assay by Biogenic Amines and Amino Acids

Abstract

Naturally occurring low molecular weight biogenic amines and amino acids were analyzed for interference in the fluorometric histamine assay. Three mechanisms of interference were detected, mimicking of histamine, suppression of histamine fluorescence and generation of increasing histamine-like fluorescence during excitation or preirradiation of the o-phthaldialdehyde condensation product with daylight or UVA light. The latter effect was seen only with amino acids. Rat peritoneal lavage fluid contained no fluorescence-suppressing substances, but there were considerable amounts of histamine-mimicking compounds which could not be digested with a diamine oxidase, and of substances generating increasing histamine-like fluorescence when exposed to UV light after condensation with phthaldialdehyde. Although butanol extraction was highly effective in selecting histamine over interfering compounds, it was not sufficient to avoid interference. In contrast, Dowex 50 W-X8 ion exchange chromatography added little to separating histamine and interfering substances. Precautions are recommended to avoid the different types of interference when biological samples are analyzed for histamine content with the fluorometric assay.

Simultaneous fluorometric measurement of histamine and tele-methylhistamine levels in rodent brain by high-performance liquid chromatography

“…However, the HPLC with precolumn derivatization method has the disadvantage of the relative instability of the derivatives and needs carefully controlled assay conditions [21,22]. Furthermore, the fact that the brain HA levels are relatively low and many biological amines concomitantly exist in the brain suggests that puriWcation and concentration steps prior to the column analysis might be beneWcial [23].…”