Paragraph 4 REAGENTS

Methanol.

Sulfuric acid solution, approximately 0.05 M.

Sodium hydroxide solution, approximately 0.1 M.

Alkaline solution of potassium sodium tartrate:

In a 1 litre graduated flask dissolve 40 g of sodium hydroxide in 500 ml of water and leave to cool. Add 50 g of potassium sodium tartrate (KNaC₄H₄O₆.4H₂O). Make up to the mark and mix. Leave standing 24 hours before use.

Copper sulfate solution:

In a 1 litre graduated flask dissolve 15 g of copper sulfate (CuSO₄.5H₂O) in 500 ml of water. Make up to the mark and mix.

Biuret standard solution:

In a 250 ml graduated flask, dissolve 0.250 g of pure biuret^f1 in water. Make up to the mark and mix. 1 ml of this solution contains 0.001 g of biuret. This solution should be freshly prepared.

Methyl red indicator solution:

Dissolve 0.1 g methyl red in 50 ml 95% ethanol and make up to 100 ml with water. Filter if necessary.