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Neutral Red pH indicator dye used in microbiology and differential culture media
  • Neutral Red pH indicator dye used in microbiology and differential culture media
  • Neutral Red pH indicator dye used in microbiology and differential culture media
Neutral Red

Neutral Red

$35.00
Weight

Neutral Red

pH Indicator Dye for Microbiology & Laboratory Research

Catalog Number: ASC-1035
CAS Number: 553-24-2
Molecular Formula: C₁₅H₁₇ClN₄
Molecular Weight: 288.78 g/mol

Overview

Neutral Red is a synthetic azo dye widely used in microbiology, histology, and laboratory research as a pH indicator and contrast stain. It exhibits a clear colour transition from red to yellow over a pH range of approximately 6.8–8.0, making it particularly valuable in culture media where metabolic acid production must be visually observed.

In microbiological media, Neutral Red is commonly incorporated as an indicator dye to differentiate microorganisms based on biochemical activity. Its well-defined colour response and stability under standard laboratory conditions make it a reliable component in routine culture media and research protocols.

Ausamics Neutral Red is supplied as a high-quality laboratory-grade dye, offering consistent colour strength, solubility, and batch-to-batch performance.

Typical Applications

Microbiology

  • Indicator dye in differential culture media

  • Visual differentiation of microbial metabolic activity

  • Widely used component of lactose-containing media

Differential Media Applications

  • Use in MacConkey-type formulations

  • Colour response linked to acid production during carbohydrate fermentation

  • Clear visual contrast between metabolically active and inactive colonies

Histology & Research

  • General laboratory staining and contrast enhancement

  • Educational demonstrations of pH-dependent dyes

  • Method development and optimisation

Principle of the Indicator

Neutral Red responds to changes in environmental pH by altering its molecular structure, resulting in a visible colour shift. In acidic conditions, the dye appears red, while in neutral to alkaline conditions it transitions toward yellow. This behaviour allows visual differentiation of microenvironments within solid or liquid culture systems under controlled laboratory conditions.

Physical & Chemical Properties

  • Appearance: Red to dark red crystalline powder

  • Solubility: Soluble in water

  • pH Transition Range: Approx. 6.8–8.0

  • Dye Class: Azo / pH indicator dye

Storage & Stability

Store in a cool, dry place at 15–25 °C.
Protect from light and moisture.
Keep container tightly sealed when not in use.

Stable under recommended storage conditions.

Intended Use

For laboratory research and educational use only.

Not for human or animal use.
Not intended for diagnostic, therapeutic, veterinary, agricultural, food, or feed applications.

Quality & Documentation

  • Certificate of Analysis (COA) available

  • Safety Data Sheet (SDS) available upon request

  • Manufactured and supplied under controlled quality conditions

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