4-Nitrophenyl phosphate, disodium salt hexahydrate is a chromogenic substrate yielding a soluble yellow chromophor for the colorimetric assay of phosphatases and is used for determining alkaline phosphatase activity in human serum.

TMB is an excellent colorimetric substrate for detection of horseradish peroxidase labeled probes and is used with peroxidase and peroxidase-coupled systems, particularly in ELISA techniques. It produces a soluble end product, which is blue in color and can be read spectrophotometrically. TMB has also been used in the quantitative determination of hemoglobin and in cytochemical staining for peroxidase. TMB is a hepatitis B antigen.

TMB is an excellent colorimetric substrate for detection of horseradish peroxidase labeled probes and is used with peroxidase and peroxidase-coupled systems, particularly in ELISA techniques. It produces a soluble end product, which is blue in color and can be read spectrophotometrically. TMB has also been used in the quantitative determination of hemoglobin and in cytochemical staining for peroxidase. TMB is a hepatitis B antigen.