Bacteriological stains
Safranin
Colouring, fixating and decolouring solutions for bacterial classification according to Gram stain.
- Cat. No.
- LC-4616
- Category
- Bacteriological stains
- Formats
- 2 formats
- Storage
- 15 to 30 °C
- Minimum guaranteed shelf life
- 15 months
The Gram stain procedure differentiates microorganisms into two groups, those which retain the primary dye (Gram-positive) and those which lose the primary dye, due to the structure of the cellular wall, and take the colour of the counterstain (Gram-negatives).
Key features
Applications
Differentiation of Gram-positive and Gram-negative bacteria.
Industry
Dyes and stains.
Principles and uses
The procedure needs four reagents: Primary dye (Oxalate Crystal Violet Solution), Iodine solution (Lugol), Decolorizer (Acetone Ethanol Decolorant) and Counter stain (Safranin Solution).
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Liquid |
| Storage | 15 to 30 °C |
Formula
| Ingredient | g/L |
|---|---|
| Ethanol | 200 |
| Safranin | 4.5 |
| Water | 795.5 |
Instructions for use
Prepare a smear and heat-fix it by gentle heating in the flame.
- Cover the smear with Crystal Violet. Let stand for 1 min.
- Remove excess by rinsing with tap water.
- Cover with Lugol and allow standing for 1 min.
- Decant and rinse with tap water.
- Decolorize with Acetone Ethanol Decolorant until waste decolorizer were colourless.
- Rinse with tap water.
- Counter stain with Safranin Solution for 1 min.
- Rinse with tap water and air dry.
Examine under an oil immersion objective.
The procedure can be modified according to the user's preferences to achieve a weaker or stronger colour intensity, being carried out by changing the times for staining, washing etc.
Old cultures or smears could give atypical results. That is why cultures of 18-24 hours or recent smears are recommended.
It is very important to control the heat-fixation (few seconds), any excess heating could produce erroneous results.
Highly chlorinated tap water could weaken the counter staining.
Quality control
Microbiological test
| Microorganism | Specification |
|---|---|
| Gram-positive bacteria | Blue-purple colonies |
| Gram-negative bacteria | Pink-red colonies |
Bibliography
- Clark, G. (1981) "Staining Procedures", 4th ed, Williams & Wilkins.
- Bartholomew J.M., Mitwer, T. (1952), Bacteriol. Rev., 16, 1-29.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
Follow your shipment live, from our warehouse to your lab.
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Frequently asked questions
Can I ask for formats other than those listed?
Yes: custom formats and OEM packs are available on request. Tell us the quantities you need.
How do I see the prices?
Prices are shown after you sign in to the customer area, with your account discount already applied.
How long does delivery take?
We give you the availability with the quote, within 24 hours of your request.