Cayman's Nitrate/Nitrite Fluorometric Assay provides a convenient method for the quantitation of low levels of nitrate and nitrite in biological samples (particularly tissue culture medium). Previously undetectable concentrations of nitrate/nitrite in a variety of samples can be accurately quantitated using this kit as it extends the lower limit of detection by 20-fold over our colorimetric version (Item No. 780001). The minimum detectable quantity of NO2/NO3 is ~50 nM.