Barfoed's Test for Monosaccharides 2.0 скачать в хорошем качестве

Barfoed's Test for Monosaccharides 2.0

Barfoed's Test is used to identify a Monosaccharide. 1 mL of Barfoed's Reagent, copper (II) acetate in acetic acid, was added to 1 mL of each sample. Samples were then heated for 2 min in boiling water, followed by cooling in an ice water bath. Monosaccharides will be oxidized in the reaction, while the copper (II) acetate will be reduced to copper (I) oxide, producing a red precipitate that will settle to be bottom of the test tube. To better identify the samples that reacted, 1 mL of phosphomolybdic colour reagent was added to each sample after heating. The copper (I) oxide will react with the phosphomolybdic to produce a dark blue colour when the phosphomolybdic is reduced. Take note that if polysaccharides and disaccharides are heated too long, the glycosidic bond may be broken, resulting in the production of monosaccharides. This may result in a false positive result of Barfoed's test. Blue colour change = Monosaccharide Negative Control = Distilled Water Negative Control = 1 % (w/v) Maltose Positive Control = 1 % (w/v) Glucose Unknowns Tested = 13 Alphabetical list of Samples all 1% (w/v) or (v/v): Acetic Acid, Albumin, Arabinose, Fructose, Galactose, Glucose, Glycerol, Glycogen, Lactose, Maltose, Starch, Sucrose, Xylose