Nitrite and nitrate can be accurately measured in samples of vegetal and animal origin using an HPLC-UV/VIS technique

► Nitrite and nitrate anions are easily determined using an HPLC-UV/VIS method. ► Nitrite is determined by pre-column derivatization using Griess reaction. ► Nitrate is simultaneously determined in UV domain. ► Limits of quantification are of ppb level for nitrite and hundreds of ppb for nitrate. ► New findings suggest that Griess reaction is not absolutely specific to nitrite.