1. Scope The method is applicable to all starch hydrolysis products.
LT 7/12 1966
Rev.: LT 3. May 1999
2. Principle The Lane and Eynon constant titre method. Mixed Fehling's solution is titrated with sample using methylene blue as indicator.
3. Reagents 3.1 Fehling stock solution A. Dissolve 69.3 g copper (II) sulphate pentahydrate (CuSO4, 5H2O) in distilled water to 1000.0 ml.
3.2 Fehling stock solution B. Dissolve 346 g potassium sodium tartrate tetrahydrate (KNaC4H4O6, 4H2O) and 100.0 g sodium hydroxide (NaOH) in distilled water to 1000,0 ml. Decant solution from sediment if necessary before use.
3.3 Methylene blue (C16H18CIN3S, 2H2O) indicator, 1% aqueous solution.
3.4 Anhydrous D-glucose pro analyse. Dry two hours at 100 oC and cool in dessicator before use.
3.5 Standard glucose solution. Weigh to the nearest 0.1 mg 1.25 g dried anhydrous D-glucose (3.4) and dissolve with distilled water to 250 ml.