• Assay Type Detection Kit
  • Sample Types Water, Serum, Plasma, Urine, Saliva, Lysates, Buffers, Tissue Culture Media
  • Sensitivity 2.63 µM (Nitrite), 1.02 µM (Total NO)
  • Species NO, Nitrate, and Nitrite are identical across species
  • Assay Duration 5 (Nitrite), 25 Minute (Total NO)
  • Samples/Plate 40 in Duplicate
  • Readout Colorimetric, 550-570 nm
  • Standard Curve Nitric Oxide (NO) Colorimetric Detection Kit
  • Description

    Assay Principle: 

    The Nitric Oxide (NO) Colorimetric Detection Kit quantitatively measures NO, Nitrate, and Nitrite levels in water, serum, plasma, urine, saliva, lysates, buffers, and tissue culture media. The Nitric Oxide (NO) Colorimetric Detection Kit is a Detection Kit with a run time of 25 minutes. Please read the complete kit insert for more information before performing this assay.

    Use our provided Nitrate and Nitrite standards to generate a standard curve for the assay. Pipette the standards or diluted samples into a transparent microtiter plate. Add Nitrate Reductase and NADH Concentrate to each well, tapping the plate to ensure sufficient mixing of reagents. The reductase, in combination with NADH, reduces Nitrate to Nitrite. Then, incubate the mixture at room temperature for 20 minutes and add Color Reagents A and B. The color-generating reaction occurs between the color reagents and the Nitrite within the sample or standard. 

    After the 5-minute incubation with the color reagents, use a plate reader to detect and record the generated signal at 540-570nm. Use the intensity and the standard curve to calculate the NO concentration in the samples.


    Nitric oxide (NO) is a diffusible, transient, reactive molecule with physiological effects in the pM-µM range. Acting through guanylate cyclase activation, NO is an essential regulator of the cardiovascular, nervous, and immunological systems. NO is bio-available by two routes: endogenous generation by constitutive or induced NOS enzymes or ingested as nitrates or nitrites for conversion into NO.

    The reactive nature of nitric oxide allows it to act as a cytotoxic factor when released during an immune response by macrophages. The reactivity also allows NO to be easily converted to a toxic radical that can produce nitrosylation damage to cells and DNA. Nitrosylation can be a regulated post-translational modification in cell signaling. The dynamics of NO’s regulatory/damage facets are significant forces in mitochondrial signaling and dysfunction. NO is linked not only to coronary heart disease, endothelial dysfunctions, erectile dysfunction, and neurological disorders but also diabetes, chronic periodontitis, autism, and cancer.