CAS · 493-52-7
Product Overview
Methyl Red is a high-purity dyes-pigments supplied for industrial and specialty chemical applications. Contact our team for specifications, packaging options and lead times.
Product Specifications
| Property | Specification |
|---|---|
| Appearance | Dark red and black crystalline powder |
| pH Color Change Interval | 4.5 (red) to 6.2 (yellow) |
| Ethanol Soluble Test | Qualified |
| Burning Residue | 2% max |
| Loss on Drying | 5% max |
Applications
1. pH Indicator in Acid-Base Titrations
● Methyl Red丨CAS 493-52-7 is commonly used in titrimetric analysis as an indicator to detect the endpoint of titrations involving strong acids and weak bases.
● It exhibits a clear and distinct color transition from red (acidic) to yellow (neutral/alkaline), which helps chemists visually determine when the reaction is complete.
2. Microbiology: Methyl Red Test (MR Test)
● A critical component of the IMViC test series (Indole, Methyl Red, Voges-Proskauer, Citrate) used to differentiate Enterobacteriaceae family bacteria.
● In the MR test, methyl red detects stable acid production from glucose fermentation by certain bacteria (e.g., Escherichia coli).
Positive result: Medium remains red (acidic, pH < 4.4)
Negative result: Medium turns yellow (pH > 6.2)
3. Educational Use in Laboratories
● Widely used in academic laboratories for demonstrating acid-base reactions, indicator properties, and spectroscopic behavior of azo compounds.
● It helps students visualize chemical changes and learn about titration and pH measurement techniques.
4. Colorimetric Assays
● Used in research settings for colorimetric detection of specific chemical species or reaction conditions.
● Can function in enzyme kinetics or reaction monitoring when pH change is a variable of interest.
5. Dye and Pigment Research
● As an azo compound, Methyl Red is also studied in dye chemistry for its structural properties, light absorption, and degradation behavior.
● Employed in research exploring azo bond cleavage and biodegradation by microorganisms.
Benefits
1. Sharp Color Transition
● Provides a vivid and reliable color shift (red to yellow) that makes endpoint detection clear and user-friendly, especially in titrations and microbial assays.
2. Stable and Reproducible
● Offers good shelf life and consistent performance under standard laboratory conditions.
● Resists degradation under normal light and temperature, ensuring accurate results in repeat experiments.
3. Widely Accepted and Standardized
● Incorporated into many standard microbiological and chemical test protocols, ensuring comparability of results across laboratories and studies.
4. Cost-effective and Easy to Use
● Inexpensive and easy to prepare as a solution in ethanol or water.
● Its simplicity and reliability make it ideal for both research and routine quality control applications.
Conclusion
Methyl Red丨CAS 493-52-7 is a trusted and versatile chemical indicator, valued in analytical chemistry, microbiology, and chemical education. Its reliable pH-dependent color change, ease of use, and low cost make it an essential tool in laboratories around the world. Whether used in acid-base titrations or the differentiation of bacterial species, Methyl Red remains a cornerstone reagent for qualitative chemical analysis.
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