A HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR HISTAMINE IN PLASMA USING SOLID-PHASE EXTRACTION AND FLUORESCAMINE DERIVATIZATION

A reversed phase HPLC method for the determination of histamine in pla sma was developed using solid phase extraction with fluorescamine deri vatization. Betazole was used as an internal standard. Histamine and t he internal standard were extracted from plasma using a cation exchang e solid phase extraction cartridge, derivatized precolumn and the deri vatized extracts were separated on a C-8, column. The solid phase extr action provided recoveries of 85-90%. The method was found to be linea r through the range of 1-10 ng/ml and the histamine derivative was sta ble at 4 degrees C for 18 hours. The method was found to be accurate t o within 7% bias and precise to within 18% CV. Selectivity could not b e rigorously assessed because of endogenous histamine, although compar ison to RIA results suggested good selectivity. The limit of detection was calculated to be 13 pg on column, although the current method was limited by the small proportion of sample injected on column. The met hod is sufficient for measuring histamine levels expected during aller gic response.