Product Identity and Physical Properties
Ethidium bromide solution (CAS 1239-45-8), IUPAC name 3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide, is a red-orange liquid commonly known as EtBr or homidium bromide. It serves as the standard intercalating dye for visualizing nucleic acids in electrophoretic gels. The compound has an empirical formula of C₂₁H₂₀BrN₃ and a molecular weight of 394.3 g/mol.
The solution appears as a clear to slightly hazy red-orange liquid with characteristic fluorescence under UV illumination. The XLogP value of 1.4 indicates moderate lipophilicity, facilitating intercalation between DNA base pairs. SMILES notation: CC[N+]1=C2C=C(C=CC2=C3C=CC(=N3)C4=CC=CC=C4)C=C1.[Br-]. This compound is a potent frameshift mutagen due to its DNA-binding mechanism.
Grade Specifications and Quality Parameters
The product is supplied as a ready-to-use solution at 10 mg/mL concentration in water. While no specific grade designation (USP, EP, BP, HPLC, or ACS) is assigned, the material is manufactured for biological applications including nucleic acid staining and fluorimetric assays. Quality Level is not explicitly defined in the provided data, but the solution meets standard requirements for molecular biology use.
| Parameter | Ethidium Bromide Solution (This Product) | Typical USP Grade | Typical ACS Grade |
|---|---|---|---|
| Concentration | 10 mg/mL | N/A (solid) | N/A (solid) |
| Physical Form | Liquid | Solid (crystalline) | Solid (crystalline) |
| Assay/Purity | Not specified | ≥95% | ≥98% |
| Impurities | Not specified | Heavy metals ≤20 ppm | Heavy metals ≤10 ppm |
| Application | Nucleic acid staining | Pharmaceutical reference | Analytical chemistry |
The solution format eliminates the need for dissolution, reducing preparation time and potential weighing errors. Impurity profiles are not detailed in the provided data; however, the product is suitable for gel electrophoresis and fluorimetric assays without additional purification. For pharmaceutical reference standard applications, users should verify compatibility with their specific analytical protocols.
Handling, Storage, and Safety
Ethidium bromide solution carries a GHS Signal Word of Danger, reflecting its classification as a mutagenic substance. Hazard codes are not fully specified in the provided data, but the compound is known to be toxic by ingestion, inhalation, and skin absorption. Storage Class and WGK (Water Hazard Class) data are not provided; however, standard practice dictates storage in a cool, dry area away from incompatible oxidizers.
Personal protective equipment (PPE) must include nitrile or neoprene gloves, safety goggles, and a lab coat. Work should be conducted in a fume hood or well-ventilated area to minimize inhalation risk. Flash point data is not available for this aqueous solution. The solution is stable when stored at 2–8°C, protected from light, with a typical shelf life of 12–24 months under recommended conditions.
Solubility and Solution Preparation
This product is supplied as a ready-to-use aqueous solution at 10 mg/mL concentration, eliminating the need for dissolution. For users requiring different working concentrations, the stock solution can be diluted in water, TAE buffer, or TBE buffer. The fluorescence of EtBr increases 21-fold upon binding to double-stranded RNA and 25-fold upon binding double-stranded DNA, enabling sensitive detection without background destaining.
For agarose gel electrophoresis, a working concentration of 0.5–1.0 µg/mL is typical. The stock solution is stable for several months at 2–8°C when protected from light. Repeated freeze-thaw cycles should be avoided to maintain fluorescence intensity. For HPLC or GC analysis, further dilution in appropriate mobile phase solvents is recommended, with concentration verification via UV-Vis spectrophotometry at 480 nm.
Applications in Analytical and Research Settings
Ethidium bromide (EtBr) is the most commonly used nucleic acid stain for PAGE or agarose gel electrophoresis. The fluorescence of EtBr increases 21-fold upon binding to double-stranded RNA and 25-fold on binding double-stranded DNA, so destaining the background is not necessary with a low stain concentration (10 µg/mL). Ethidium bromide has been used in a number of fluorimetric assays for nucleic acids. It has been shown to bind to single-stranded DNA (although not as strongly) and triple-stranded DNA. Because of its ability to bind to DNA, EtBr is an inhibitor of DNA polymerase.
The 10 mg/mL stock solution provides sufficient material for approximately 1000 gel staining runs at 10 µg/mL working concentration (assuming 100 mL staining volume per gel). The solution is suitable for fluorimetric assays, DNA polymerase inhibition studies, and combination staining with acridine orange for differential nucleic acid visualization. For HPLC applications, the compound can be detected at 254 nm or 480 nm with appropriate method validation.
Supplier Selection Guide
Research quantities of Ethidium bromide solution (CAS 1239-45-8) are available from major suppliers. For bulk production, formal quotations with CoA, SDS, and lead time are available within 24 hours — contact our team to inquire about current pricing and discuss your requirements.
A: Ethidium bromide solution is primarily used as a nucleic acid stain for visualizing DNA and RNA in agarose and PAGE gels. It is also employed in fluorimetric assays for nucleic acid quantification and as a DNA polymerase inhibitor in molecular biology research.
A: The grade designation is not explicitly defined in the provided data. The product is manufactured as a ready-to-use solution for biological applications, meeting standard requirements for nucleic acid staining and fluorimetric assays without additional purification steps.
A: Store the solution at 2–8°C, protected from light, to maintain fluorescence activity. Avoid freeze-thaw cycles. Under these conditions, the solution typically remains stable for 12–24 months. Always check for precipitation or color change before use.
A: UV-Vis spectrophotometry at 480 nm (absorption maximum) confirms concentration. HPLC with UV detection at 254 nm or 480 nm can assess purity and detect degradation products. Fluorescence spectroscopy (excitation 302 nm, emission 590 nm) validates nucleic acid binding activity.
A: Standard documentation includes a Certificate of Analysis (CoA) confirming concentration and appearance, and a Safety Data Sheet (SDS) detailing handling precautions and first aid measures. Additional documentation such as GMP certificates may be available upon request for regulated applications.
Ethidium bromide solution
CAS: 1239-45-8
Form: Liquid, 10 mg/mL
Application: Nucleic acid staining for gel electrophoresis and fluorimetric assays
