PRAPARATION OF FEHLING’S SOLUTIONS

PRAPARATION OF FEHLING’S SOLUTIONS

Fehling solutions are vital reagent for Biochemist and Chemists for qualitative and quantitative analysis of carbohydrates in the laboratory. It was first prepared by Hermann Von Fehling.

The following are the standard procedure for the preparation of Fehling I and II solutions.

Preparation of Fehling I solution

APPARATUS: 500ml Beaker, stirrer, 1000ml volumetric flask

REAGENT: Distilled water, CuSO₄ powder

PROCEDURE:

1.      Weigh 69.3g of CuSO4 powder into a 500ml beaker, add 200ml distilled water and stir to dissolve

2.      Transfer to 1000ml volumetric flask, make up to the mark with distilled water and shake to homogenise

 

Preparation of Fehling II solution

REAGENT: Distilled water, NaOH pellets, Potassium sodium tartarate powder

PROCEDURE:

1.      Weigh 100g of NaOH pellets into a 500ml beaker, add 200ml distilled water and stir to dissolve

2.      Weigh 346g of potassium sodium tartarate into another 500ml beaker, add 300ml distilled water and stir to dissolve

3.      Transfer both solutions to 1000ml volumetric flask, make up to the mark with distilled water and shake

NB: The above preparations are for the preparation of 1 litre of the resulting solution.