Thermo Scientific Pierce 1-Step Chloronaphthol Solution is a solution of 4-chloro-1-naphthol for the chromogenic detection of horseradish peroxidase (HRP) activity in Western blot and tissue staining methods. Chloronaphthol (4-CN, MW = 178.6) reacts with HRP to form a distinct blue to blue-purple product to localize and visualize the activity of peroxidase-conjugated antibodies on blots or fixed tissue samples. The HRP substrate is not as sensitive or stable as other chromogenic substrates, such as TMB and DAB. However, the blue-purple precipitate photographs well, and its alcohol-solubility is a property that can be utilized in certain double-staining applications. Features of Chloronaphthol Substrates: HRP substrate—for detection of horseradish peroxidase activity on solid media Chromogenic—no special equipment needed for visualization Blue-purple—easy to photograph in color or black-and-white Package options—choose powder or ready-to-use solution Highlights of Pierce CN Solution Ready-to-use—no ethanol or methanol required to dissolve; no dilution necessary for use Complete—does not require buffer or addition of hydrogen peroxide Pre-filtered—does not need to be filtered before use like powders or tablets after they are dissolved Stable—store refrigerated at 4°C for at least one year