
Auramine O is a diarylmethane dye that works as a fluorescent stain. It occurs as a yellow needle crystal in its pure state. It is frequently used to stain acid-fast bacteria, where it bonds to the mycolic acid in the bacterial cell wall, and can also be engaged as a fluorescent alternative to the Schiff reagent. Further, it is often used together with Rhodamine B in staining techniques.

CAS No.: 2465-27-2
Synonyms: Auramine hydrochloride; Basic yellow 2; Pyocatanium aureum; Aizen auramine; Pyoktanin yellow; Canary yellow, pyoktanin; Auramin; Benzophenoneidum; Calcozine Yellow OX
Resources:Â
| Physical Properties | |
| Chemical formula | C17H22ClN3 |
| IUPAC Name | Â 4-[4-(dimethylamino)benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride |
| Molecular weight | 303.8 g/mol |
| Solubility | Ethanol and DMSO |
| Insoluble | Water |
| Flash point | 199.4°C |
| Density | 1.01–1.07 g/cm3 |
| Chemical Properties | |
| Color | Â Yellow |
| State | Powder or flakes |
| Melting point | >250°C |
| Vapor Pressure | 8.31E-07mmHg at 25°C Vapor |
| pH | 6.5 |
| LogP | 4.13650 |
| Pictograms : | ![]() ![]() ![]() |
| Hazard Statements : | H302: Harmful if swallowed |
| Precautionary statements : | P273: Avoid release to the environment P280: Wear protective gloves/eye protection P301+P312: IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present, and easy to do. Continue rinsing P308+P313: IF exposed or concerned: Get medical advice/attention P337+P313: If eye irritation persists: Get medical advice/attention |
Auramine O is a diarylmethane dye that works as a fluorescent stain. It occurs as a yellow needle crystal in its pure state. It is frequently used to stain acid-fast bacteria, where it bonds to the mycolic acid in the bacterial cell wall, and can also be engaged as a fluorescent alternative to the Schiff reagent. Further, it is often used together with Rhodamine B in staining techniques.

CAS No.: 2465-27-2
Synonyms: Auramine hydrochloride; Basic yellow 2; Pyocatanium aureum; Aizen auramine; Pyoktanin yellow; Canary yellow, pyoktanin; Auramin; Benzophenoneidum; Calcozine Yellow OX
Resources:Â
| Physical Properties | |
| Chemical formula | C17H22ClN3 |
| IUPAC Name | Â 4-[4-(dimethylamino)benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride |
| Molecular weight | 303.8 g/mol |
| Solubility | Ethanol and DMSO |
| Insoluble | Water |
| Flash point | 199.4°C |
| Density | 1.01–1.07 g/cm3 |
| Chemical Properties | |
| Color | Â Yellow |
| State | Powder or flakes |
| Melting point | >250°C |
| Vapor Pressure | 8.31E-07mmHg at 25°C Vapor |
| pH | 6.5 |
| LogP | 4.13650 |
| Pictograms : | ![]() ![]() ![]() |
| Hazard Statements : | H302: Harmful if swallowed |
| Precautionary statements : | P273: Avoid release to the environment P280: Wear protective gloves/eye protection P301+P312: IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present, and easy to do. Continue rinsing P308+P313: IF exposed or concerned: Get medical advice/attention P337+P313: If eye irritation persists: Get medical advice/attention |
It’s a fluorescent staining method that detects acid-fast bacteria like Mycobacterium tuberculosis. It includes staining with Auramine O and using phenol as a mordant to help the dye pierce bacterial cell walls.
Auramine O emits a bright yellow-green fluorescence when exposed to ultraviolet (UV) light.
When the cells stained with Auramine O are observed under ultraviolet light, they appear bright yellow-green or red-orange.
Auramine O staining is often more sensitive than ZN staining, as research shows up to a 10% improvement in sensitivity. It is also faster and more efficient, due to lower magnification and quicker smear examination.
Auramine O phenol stain is a fluorescent stain that appears yellowish-green in contrast to a dark background.