A Rapid Qualitative and Quantitative Method of Assaying Histamine in Small Plasma Volume

A modified method for a qualitative and quantitative determination of histamine in small plasma volume (≤300 μl) was developed. According to this method, blood samples containing methylhistamine, the internal standard, are centrifuged to collect plasma. These plasma samples which contain underivatized histamine are injected into a Dionex BioLC System coupled with a pulsed amperometric detector. Histamine and methylhistamine are separated through a C-18 Zorbax ODS 4.5mm ID ± 25cm (5 microns) column. Histamine is quantitated by comparing histamine peak height with that of known quantity of the internal standard. The sensitivity of the method is 0.03 pmols. The peak heights were found to be linearly related to histamine concentrations providing a quantitative means of assaying histamine in biological samples. The retention time of histamine was 6 min in contrast to that of methlyhistamine which was 10 min.