The Nitric Oxide Assay Kit determines nitric oxide composition through measurement of nitrate (NO₃) and nitrite (NO₂) levels in urine, saliva, plasma, serum, and other biological fluids.

Characteristics of the Nitric Oxide Assay Kit:

Target: nitric oxide and relative levels of nitrite and nitrate
Format: colorimetric stain (azo dye) for clear 96-well plates
Measurement: absorbance at 540 nm (±20 nm)
Assay range: 0 to 100 μM
Sensitivity: 0.222 μM nitrite; 0.625 μM nitrate
Precision: dependent upon several factors (generally, intra- and inter-assay CV ≤ 5%)
Sample types: urine, saliva, plasma, serum, and other biological fluids
Total assay time: 15 minutes (nitrite assay); 45 minutes (nitrate assay)
Sample size: 50 μL

The Nitric Oxide Assay Kit is for quantitative determination of nitrite and nitrate in biological fluids. The kit uses the enzyme nitrate reductase to convert nitrate to nitrite. Nitrite is then detected as a colored azo dye product of the Griess reaction that absorbs visible light at 540 nm. The interaction of nitric oxide in a system is measured by the determination of both nitrate and nitrite concentrations in the sample. The relative levels of nitrite and nitrate can vary substantially, therefore the most accurate determination of total NO production requires measurement of both nitrate and nitrite.

See manual for sample preparation guidelines, sample-specific tips, and calculations.

Includes:
Griess reagents, nitrite and nitrate standards, nitrate reductase, NADH, and diluents.

Two microplates are necessary to perform this assay. One plate is used to measure the amount of nitrite in each sample. For the second plate, all of the nitrate in each sample is converted to nitrite using nitrate reductase enzyme and the “total” amount of nitrite (pre-existing nitrite plus nitrate that was converted) is measured. The nitrite measurements from plate 1 are subtracted from the total nitrite measurements in plate 2 in order to calculate nitrate concentrations. This kit is specifically designed for researchers concerned with the relative levels of nitrate and nitrite in each sample.