Sulforhodamine B CAS 3520-42-1

What is Sulforhodamine B CAS 3520-42-1?

Sulforhodamine B CAS 3520-42-1 is a complex organic compound formulated as a highly water-soluble sodium salt. Typically supplied as a brown to very dark purple solid powder, it is manufactured through the precise condensation of 4-formylbenzene-1,3-disulfonic acid and 3-(diethylamino)phenol, followed by dehydration and oxidation. Upon dissolution in water, it forms a bright bluish-red solution characterized by strong yellow fluorescence. Functioning as a membrane-impermeant polar tracer, it binds stoichiometrically to basic amino acids in cellular proteins, making it an indispensable biochemical reagent for accurate cell mass quantification, as well as an effective industrial acid dye.

Specifications

Features

• Stoichiometric Protein Binding – Binds to the protein constituents of cells in a highly proportional and predictable manner, allowing the extracted dye to accurately and reliably represent total cell mass.
• High Fluorescent Yield – Exhibits a distinct maximum absorption wavelength at 554 nm, delivering strong, stable yellow fluorescence that is highly effective for precise microscopic tracing and assay readouts.
• Excellent Aqueous Solubility – Dissolves efficiently and completely in water (achieving up to 95.3 g/L at 20 °C) and methanol, ensuring smooth, homogenous integration into biological assay buffers and industrial liquid dye baths.

Applications

• In Vitro Cytotoxicity Assays – Critically utilized in the standard SRB assay for high-throughput laboratory drug screening, precise relative total cell mass quantification, and live-cell proliferation observation.
• Biological & Medical Imaging – Serves as an advanced microscopic tracer for assessing blood-brain barrier integrity in frozen sections, detecting caries in histological material, and functioning as a molecular rotor for microviscosity determination.
• Textile & Cosmetic Coloration – Applied commercially as an industrial acid dye for the high-quality coloring and printing of wool, silk, and polyamide fibers, as well as acting as a functional colorant in cosmetics and nonpermanent tattoos.

Packaging

Mikem offers flexible packaging options, including 25 kg of fiber drums for liquid products and 15–25 kg PP/PE bags for powder products, all customizable to meet your specific needs.