Technical Parameters

Description

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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

Transport Information

Parameter	Specification
UN Number
Class
Packing Group
H.S. Code	2934991000999
Stability & Reactivity	The product is chemically stable under standard ambient conditions.
Storage	Tightly closed. Store in a closed, dry, ventilated place
Condition to Avoid
Package

Manufacturing Information

Parameter	Specification
Capacity	1MT/month
Frequency
Main Export Countries
Capacity/Batch
Experience	Production since 2009
Stock

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This diagnostic application has largely been replaced by more modern techniques but is of historical significance.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.