Frequently Asked Questions Live Chat and Frequently Asked Questions are available for this Product. Application Substrate for alkaline phosphatase that yields a soluble yellow end product that may be read at 405 nm. The reaction may be stopped with 3N NaOH and read at 405 nm. Recommended for ELISA (microwell) procedures, not recommended for membrane applications. Caution Stable at least one year when stored below 0 °C. Physical form Ready-to-use.