94635

Gram′s safranin solution

for microscopy

• Synonym(s): Safranin T solution
• Empirical Formula (Hill Notation): C₂₀H₁₉ClN₄
• CAS Number: 477-73-6
• Molecular Weight: 350.84
• Beilstein/REAXYS Number: 3924099
• MDL number: MFCD00011759
• UNSPSC Code: 12171500
• PubChem Substance ID: 329770368
• NACRES: MA.02

Properties

• grade: for microscopy
• Quality Level: 100
• form: liquid
• shelf life: limited shelf life, expiry date on the label
• composition: ethanol, 10%
• technique(s): microbe id | staining: suitable
• color: red to very dark red
• refractive index: n20/D 1.339
• solubility: water: soluble at 20 °C
• density: 0.986 g/mL at 20 °C
• εmax: 4.0 at 532 nm in 50% ethanol
• antibiotic activity spectrum: Gram-negative bacteria; Gram-positive bacteria
• application(s): diagnostic assay manufacturing; hematology; histology
• storage temp.: room temp
• SMILES string: [Cl-].Cc1cc2nc3cc(C)c(N)cc3[n+](-c4ccccc4)c2cc1N
• InChI: 1S/C20H18N4.ClH/c1-12-8-17-19(10-15(12)21)24(14-6-4-3-5-7-14)20-11-16(22)13(2)9-18(20)23-17;/h3-11H,1-2H3,(H3,21,22);1H
• InChI key: OARRHUQTFTUEOS-UHFFFAOYSA-N

Description

General description

Gram’s safranin solution, also known as Safranin T or Basic Red 2, is a ready-to-use staining solution that comprises 10% safranin in ethanol. Safranin is a basic, cationic, azine dye containing a planar, diaminophenazine chromophore, with a phenyl substituent attached to a ring nitrogen. The trimethyl cationic form of safranine is lipophilic, whereas the dimethyl forms are weakly hydrophilic. It is most notably used in bacteriology as a counterstain in Gram staining to differentiate between Gram-positive and Gram-negative bacteria.

Application

Gram’s safranin solution has been used in the following applications:

• as a non-toxic replacement for crystal violet for the quantification of biofilm formation
• to develop a hyaluronic acid visualization method
• to study improved β-lactam susceptibility against biofilm-embedded staphylococcus aureus by 2-aminothiazole

Features and Benefits

• Ready-to-use solution.
• Modified and designed in such a way that staining can be carried out in staining cells, on the staining rack, and in automated staining systems.

Principle

Gram staining enables the differentiation of bacteria into Gram-positive and Gram-negative. The mureine structure of the bacterial cell wall is the basis of the color affinity. Bacteria are first stained with crystal violet, and then with iodine solution, which forms a dye-iodine complex. This complex is retained in the multi-layer mureine structure of the cell wall of Gram-positive bacteria after decolorization, imparting a blue-violet color. The cell wall of Gram-negative bacteria comprises a single-layered murein structure that does not retain the dye-iodine complex, allowing the uptake of safranine counterstain, and imparting a pink-red color.

Safety Information

• pictograms: GHS02
• signalword: Warning
• hcodes: H226
• pcodes: P210 - P233 - P240 - P241 - P242 - P243
• Hazard Classifications: Flam. Liq. 3
• Storage Class: 3 - Flammable liquids
• wgk_germany: WGK 2
• flash_point_f: 114.8 °F
• flash_point_c: 46 °C
• ppe: Eyeshields, Faceshields, Gloves, type ABEK (EN14387) respirator filter