Simultaneous determination of histamine and prostaglandin D_2 using an LC-ESI-MS/MS method with positiveegative ion-switching ionization modes: Application to the study of anti-allergic flavonoids on the degranulation of KU812 cells

摘要

A new method for simultaneous determination of histamine and prostaglandin D_2 (PGD_2) by liquid chromatography-electrospray ionization tandem mass spectrometry operated in positive and negative ionization switching modes was developed and validated without a previous derivatization step. This method was used to measure histamine and PGD_2 release following degranulation of KU812 human basophilic cells, using pyrazol and d 4-PGD_2 as internal standards. Analyses were performed on a liquid chromatography system employing a Cosmosil 5C_(18) PAQ column and an isocratic elution with mixed solution of methanol-water (7:3, v/v) with 0.0015% trifluoroacetic acid at a flow rate of 0.2 mL/min. A triple-quadrupole mass spectrometer operating in selected reaction monitoring mode simultaneously monitored using the following transitions: positive m/z 112/95 for histamine and negative m/z 351/271 for PGD_2. The retention times of histamine and pyrazol were 4.2 and 5.0 min, respectively. PGD_2 and d 4-PGD_2 had retention times of 8.5 min. The limits of detection were 0.3 and 0.5 ng/mL for histamine and PGD_2, respectively. The relative standard deviations of the retention time and peak area for histamine were between 1.6% and 7.7%, and were 1.2% and 7.8% for PGD_2. This method was used to evaluate the anti-allergic effects of 26 flavonoids and sodium cromoglicate which are first-line anti-allergic drugs. Of these compounds, baicalein and morin were the most potent inhibitors.