p-Nitrophenyl Phosphate Substrate (pNPP)

TitleQuantityAdd to cart
p-Nitrophenyl Phosphate Substrate (pNPP) 20 mg
p-Nitrophenyl Phosphate Substrate (pNPP) 20 mg
p-Nitrophenyl Phosphate Substrate (pNPP) 5 mg
p-Nitrophenyl Phosphate Substrate (pNPP) 5 mg
pNPP tablet


  • Formulated from analytical grade reagents
  • Specifically developed for immunoassays
  • Chromogenic substrate                     
  • Reproducibility from lot to lot
  • Exactly pre-weighed tablets



Product description

Medicago’s pNPP substrate is specifically developed for immunoassay procedures and it is ideal for phosphate-based ELISA methods. The substrate is also used as a chromogenic non-specific substrate in alkaline and acid phosphatase assays. Its soluble end-product is yellow and can be spectrophotometrically read at 405 to 410 nm. The reaction may be stopped with 3 M NaOH.

The pNPP substrate is supplied as pre-weighed tablets in bottles or in convenient blister packs, each tablet containing 5 mg or 20 mg of substrate.



  • Immunoassays
  • Chromogenic substrate for phosphatase assays
  • Histochemistry procedures
  • Recommended for ELISA procedures


Directions for use

Deposit one tablet of the pNPP substrate in a laboratory flask or beaker placed on a magnetic stirrer. Add deionized water in the appropriate amount to reach the required concentration for the assay. Stir until full dissolution and the substrate solution is ready to use.


Shipping and storage

The pNPP substrate is shipped at room temperature. Store the tablets in a dark place below -18°C. Shelf life is three years after production date.



Chemicals: Analytical grade

Format: Exactly pre-weighed tablets

Weight: 5 mg and 20 mg