Borfoed’s Test. To distinguish whether the reducing sugar is monosaccharide or disaccharide. Borfoed’s test is basically meant to detect monosaccharide's in acidic PH but it can also be used to distinguish b/w monosaccharide's and disaccharides by controlling the time of heating . Reagents .
Borfoed’s test is basically meant to detect monosaccharide's in acidic PH but it can also be used to distinguish b/w monosaccharide's and disaccharides by controlling the time of heating
Borfoed's reagent consists of
Glacial Acetic Acid
It is prepared by dissolving 24gm copper acetate in 400ml of boiling water to this add 25ml of 8.5% glacial acetic acid solution, stirr and cool the solution and then add distilled water to make the volume 500ml.
When sugars having free aldehydic or ketone group healed with Borfoed's reagent in acidic Medium and boiled, reducing monosaccharide's reduce copper ions into cupric ions and then into cuprous ions this test differs from Benedict's test in aspect that the reduction of cupric ions is carried out in a mildly acidic Medium.
Aldoses and Ketoses can reduce cupric ions ever in acidic conditions, since acidic medium is unfavourable for reduction only. The strongly reducing carbohydrates i.e. monosaccharide's react very fast and give positive test with in 3 minutes.
Disaccharides can also give this test positive. They are bolied for sufficient time enough to hydrolyze them in the presence of Acidic medium
Take 2ml of barfoed’s reagent and 2ml of given solution in a test tube. Mix the contents thoroughly note the time by your watch.
Place the test tube in a boling water bath for 5 minutes.
Remove the test tube from boiling water and cool under running tap water. Note the appearance of precipitates if precipitates do not appear put the test tube in the boiling water bath for 15m and note the appearance of precipitates.
If the red precipitates appear at the bottom of test tube in 5m it indicates that the carbohydrates under testing is a monosaccharide's if precipitates appear after 15m of heating it indicates that the carbohydrate under testing is disaccharides.
Chloride ions interfere with this test therefore, the test should not be carried out with solutions containing chloride ions e.g. urine.