Division 4 Reagents

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1. 4.1Division 4.1
2. 4.2Division 4.2
3. 4.3Alkaline copper reagent: dissolve 25 g of anhydrous sodium carbonate and 25 g of potassium sodium tartrate tetrahydrate in about 600 ml of water containing 40 ml of 1.0 mol/litre sodium hydroxide. Dissolve 6·0 g of copper II sulphate pentahydrate (CuSO4.5H2O) in about 100 ml of water, and add to the tartrate solution. Dilute to one litre with water.
4. 4.4Standard invert sugar solution: dissolve 23·750 g of pure sucrose (4.5) in about 120 ml of water in a 250 ml graduated flask, add 9 ml of hydrochloric acid (ζ = 1·16) and allow to stand for eight days at room temperature. Make the solution up to 250 ml and check for completion of hydrolysis by a polarimeter or saccharimeter reading in a 200 mm tube. This should be - 11·80o ± 0·05 oS (see Note 8). Pipette 200 ml of this solution into a 2 000 ml graduated flask. Dilute with water and while shaking (to avoid excessive local alkalinity) add 71·4 ml of sodium hydroxide solution (1 mol/litre) in which 4 g of benzoic acid has been dissolved. Make up to 2 000 ml to give a 1 g/100 ml solution of invert sugar. This solution should be approximately pH 3.
5. 4.5Division 4.5