Basic Fuchsin Reagent

Preparation of Basic Fuchsin Reagent ("Cold" Method)

Perform the preparation of the reagent under a fume hood or in a very well ventilated area (irritating sulphur dioxide fumes are given off during preparation of the reagent).

Wear protective gloves and safety glasses and protect your clothes.

Ingredients:

• Basic Fuchsin C.I. 42510 (or New Fuchsin C.I.42520), 1g

• Potassium or sodium metabisulphite, 2.8g (potassium or sodium metabisulphite can deteriorate on storage (try and obtain a relatively fresh batch)

• Hydrochloric acid (ex pool shop)

• Add 1.5ml of the concentrated acid to 100ml of distilled (or deionised water ex Woolworths)

• Activated charcoal

1. Prepare 100ml of the hydrochloric acid solution, by adding 1.5ml of concentrated hydrochloric acid to 100ml of water (remember "Always do what you oughta, add the acid TO the water").

2. Dissolve the metabisulphite in the acid solution (if you put the metabisulphite in the solution first, you can see when it is dissolved before then adding the Basic Fuchsin).

3. Add the Basic Fuchsin and mix thoroughly (to facilitate "wetting", damp the powdered dye with a little alcohol).

4. Stopper the container with a lid or parafilm to stop the loss of sulphur dioxide.

5. Shake the solution periodically until it turns a yellow to light brown colour. This takes at least 2 hours or more. The final Schiff's Reagent is a "water white" (clear solution), and to get rid of the yellowish/brown impurity present in most samples of Basic Fuchsin that does not decolourise under the action of the sulphite, the solution is treated with activated charcoal which removes the impurities. You may wish to forego this step.

6. Add half a teaspoon of activated charcoal to the solution, and shark or stir the solution for 1?2 minutes, then filter through filter paper in a plastic funnel.

7. Repeat step 5 until the solution is clear.

8. Transfer the reagent to a clean, stoppered bottle, label, and store in a fridge.

9. You will know if the reagent works, as any spilled solution will turn a bright magenta colour.

Notes:

• Prepare the reagent in a suitable lidded glass jar or a container, or sealed with parafilm;

• Weigh the ingredients using a good set of digital scales;

• Weigh the chemicals onto a pre?folded slip of paper or a piece of aluminium foil to facilitate transfer to the container;

• Measure the concentrated hydrochloric acid with a plastic syringe