BluePhos® Microwell Substrate Kit

Size Material # List Price
600 mL 5120-0059 Contact Us
2.7 L 5120-0060 Contact Us
50 mL 5120-0061 Contact Us


BluePhos® Microwell Phosphatase Substrate System is a soluble, proprietary form of 5-bromo-4-chloro-3-indolyl phosphate (BCIP) designed for use with alkaline phosphatase-labeled antibodies. This substrate produces a deep blue color and features greater sensitivity, wider working range, lower background, and more convenience than pNPP. The addition of APStop Solution halts further color development without significantly altering the absorbance value.

Product Highlights

  • Provides greater sensitivity than traditional pNPP substrates
  • Excellent linearity and signal-to-noise
  • Easy-to-see color change upon stopping


  • Detection Method: Colorimetric ELISA
  • Measurement: 595 - 650 nm
  • Stability: 2 years from date of receipt
  • Storage: 2 -  80oC

Comparison of AP Colorimetric Substrates for ELISA

Human IgG was serially diluted in an ELISA plate and detected with 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.