Kinetic studies on nitrite and nitrate in rats by ion-pair chromatography.

A highly sensitive and specific ion-pair chromatographic method is presented for the simultaneous determination of nitrite (NO2-) and nitrate (NO3-) in plasma. The detection limits are 2 mumol NO2-/l and 8 mumol NO3-/l with recovery rates of 98-99%. The applicability of this method to clinical medicine is demonstrated using NO2- -loaded rats as a biological model: following intravenous infusion or intragastric application of NO2-, blood levels of NO2-, NO3- and methemoglobin are measured during 2-64 min. The kinetic data obtained reflect the complex metabolism of NO2- and NO3- in living organisms.