The TMB Liquid Substrate System is widely used in immunoassays, particularly in ELISA (Enzyme-Linked Immunosorbent Assay) applications. It serves as a chromogenic substrate for horseradish peroxidase (HRP), producing a blue color upon reaction, which can be measured spectrophotometrically. This system is favored for its sensitivity, stability, and ease of use, making it suitable for detecting low concentrations of target analytes in biological samples. Additionally, the reaction can be stopped with an acid, turning the solution yellow for quantitative analysis. It is commonly employed in clinical diagnostics, research laboratories, and biopharmaceutical industries for detecting antibodies, antigens, and other biomarkers.