CAS · 143-74-8
Product Overview
Phenol 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
| Appearance: | Tender red color, deep red crystalline powder |
|---|---|
| Indicator Grade pH (Color domain): | 1.2 (Orange) ~ 3.0 (Yellow); 6.5 (Brownish yellow) ~ 8.0 (Purple) ~ 8.2 (Red) |
| Maximum absorption wavelength: | pH 1.2: 503~506 nm pH 3.0: 430~435 nm pH 6.5: 430~435 nm pH 8.0: 557~560 nm |
| Mass absorptivity: | pH 1.2: 110~123 L/(cm·g) pH 3.0: 60~68 L/(cm·g) pH 6.5: 62~72 L/(cm·g) pH 8.0: 120~135 L/(cm·g) |
| Loss on drying: | 1.0% max |
| Residue on ignition: | 0.2% max |
| Alkali dissolution test: | Qualified |
Applications
1. pH Indicator in Cell Culture
Phenol red is most widely used as a pH indicator in:
Cell culture media (e.g., DMEM, RPMI-1640): Changes color based on pH to signal contamination or metabolic changes.
Yellow indicates acidic (low pH), red neutral, and purple alkaline (high pH).
2. Medical Diagnostics
Formerly used in kidney function tests, where it was injected intravenously and its clearance monitored (Phenol Red test).
This diagnostic application has largely been replaced by more modern techniques but is of historical significance.
3. Laboratory Reagent
Used in titrations and other chemical experiments as a visual pH indicator.
Common in aqueous and biological systems to monitor pH changes in real time.
4. Research Applications
Acts as a tracer dye or colorimetric marker in lab assays.
Occasionally used in biosensors and detection systems due to its reliable color change.
5. Histological Staining
Can be part of certain staining protocols to highlight structures under a microscope, particularly in plant or cell wall studies.
Benefits
Clear Visual Feedback: Provides easy-to-read color transitions (yellow to red to purple) around neutral pH.
Biocompatibility: Widely accepted in biological and cell culture contexts.
Low Cost and Accessibility: Readily available and inexpensive, with widespread use across scientific disciplines.
Stable Compound: Chemically stable under standard lab conditions, ensuring long shelf life and reliability.
Non-Destructive to Cells (at proper concentrations): Typically used at low concentrations (15–20 mg/L) that do not interfere with cell growth or assay results.
Conclusion
Phenol Red (CAS 143-74-8) is a trusted and essential reagent in laboratories, especially in cell culture and analytical chemistry. Its ability to clearly indicate pH changes with color transitions makes it an invaluable tool for maintaining and monitoring biological systems. Despite minor limitations-such as weak estrogenic effects-its advantages, stability, and cost-effectiveness ensure its continued widespread use in research and diagnostic settings.
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