To Determine the Blood Glucose Levels by
Folin and Wu Method^14
14.1 Principle........................................
The test is based on reducing property of glucose in hot alkaline solution. Proteins
are precipitated by tungstic acid and removed by centrifugation. Protein-freefiltrate
of plasma contains glucose that reduces cupric ions of alkaline CuSO 4 to cuprous
oxide, which in turn reduces phosphomolybdic acid to molybdenum blue, and color
thus produced is measured colorimetrically at 430 nm.
14.2 Reagents........................................
1.N/12 H 2 SO 4 acid: 0.25 ml conc. H 2 SO 4 is diluted to 100 ml with distilled water.
2.Sodium tungstate (10%): Dissolve 1 g sodium tungstate in distilled water to
makefinal volume of 10 ml.
3.Alkaline copper sulfate reagent
Sol. A–Dissolve 0.9 g of CuSO 4 .5H 2 O in 50 ml of distilled water.
Sol. B–Dissolve 0.8 g of Na 2 CO 3 and 0.15 g of tartaric acid in 50 ml distilled
water. Mix solution A and B in equal volume to form solution of alkaline
CuSO 4.
4.Phosphomolybdic acid: Dissolve 3.5 g of phosphomolybdic acid and 0.5 g of
sodium tungstate and 2.0 g of NaOH in about 20 ml of distilled water. Boil for
30 – 40 min for removal of ammonia. Cool and add slowly 1.25 ml of phosphoric
acid (H 3 PO 4 ) with constant stirring, and make thefinal volume to 50 ml with
distilled water.
5.Glucose standard stock solution (500 mg/dl): Dissolve 500 mg of glucose in
saturated benzoic acid solution (0.2%) and make up to 100 ml with it.
6.Working glucose standards: Prepare 25, 50, 75, 100, 200, 400, and 500 mg %
glucose solutions by diluting the stock glucose standard with saturated
benzoic acid.
#Springer Nature Singapore Pte Ltd. 2018
V. Kumar, K. D. Gill,Basic Concepts in Clinical Biochemistry: A Practical Guide,
https://doi.org/10.1007/978-981-10-8186-6_14
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