1. Weigh 1.50 g of cupric sulfate pentahydrate (CuSO4 5 H2O) with 6.0 g sodium potassium tartrate tetrahydrate (NaKC4H4O6 4 H2O).
2. Dissolve in 500 ml of H2O.
3. Add 300 ml of 10% NaOH.
4. Make up to total volume of 1 liter. Store in a plastic bottle protected from light.
Gornall, A.G., Bardawill, C. J. and David, M. M. (1949)
Determination of Serum Proteins by means of the Biuret Reaction.
J. Biol. Chem. 177; 751.