pNPP Microwell Tablets

  • Size

    500 mg

  • List Price


  • Unit


  • Inventory Status

    In Stock

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Substrate that contains para-nitrophenylphosphate (pNPP). Designed for use with alkaline phosphatase-labeled conjugates. It develops a yellow color measurable between 405-410 nm. pNPP Microwell Substrate Tablets, when used with DEA buffer, develop a soluble yellow color in the presence of alkaline phosphatase conjugates in ELISA applications. This substrate is recommended for use with KPL's DEA Buffer to produce a working substrate. The substrate reaction can be stopped with an equal volume of APStop™ Solution.

Product Highlights:

  • Economical choice for standard alkaline phosphatase-based ELISA
  • Wide linear range of working substrate
  • Simply dissolve in DEA buffer, mix, and use.


  • Detection Method: Colorimetric ELISA
  • Measurement: 405 - 415 nm
  • Stability: 1 year from date of receipt
  • Storage: 2 - 8°C

Comparison of AP Colorimetric Substrates for ELISA

Human IgG was serially diluted in an ELISA plate and detected with goat anti-human IgG labeled with alkaline phosphatase. KPL's substrates, BluePhos®, FirePhos™, pNPP, and a competitor pNPP were added to the plate. The reactions were stopped with APStop Solution and read at the recommended wavelength for each substrate.