Neutral Red
Catalog Number: ASC-1035
CAS Number: 553-24-2
MW: 288.78 g/mol
MF: C15H17ClN4
Neutral red is a versatile dye with applications in both histology and microbiology. As a pH indicator, it changes color from red to yellow within a specific pH range (typically 6.8-8.0). This property makes it valuable in microbiology for differentiating bacteria based on their ability to ferment. In MacConkey agar, for example, neutral red along with lactose helps identify lactose fermenters. When bacteria ferment lactose, they produce lactic acid, lowering the surrounding pH. This acidic environment causes the neutral red to remain red in lactose-fermenting colonies, contrasting with the pale colonies of non-fermenters where the neutral red appears yellow due to the higher pH.
Neutral Red
Cat. Number ASC-1035 CAS Number 553-24-2 MDL Number MFCD00012651 PubChem 310277720 Molecular Weight 288.78 g/mol Molecular Formula C15H17ClN4 Storage Temperature +20°C Form and Color Powder, Green, Brown or Black Solubility (0.1% in 50% EtOH + 2ml HOAc) Clear, Red Solution Wavelength of Maximum Absorption (λmax) 535.0 – 545.0 nm Absorptivity (1%/1cm) ≥ 1350 (at λmax) Loss on Drying ≤ 10.0% (1h, 110°C) Dye Content (Spectrophotometry) ≥ 90.0%
