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Barfoed's test is a chemical test used for detecting the presence of monosaccharides. It is based on the reduction of copper(II) acetate to copper(I) oxide (Cu 2 O), which forms a brick-red precipitate. [1] [2] RCHO + 2Cu 2+ + 2H 2 O → RCOOH + Cu 2 O↓ + 4H + (Disaccharides may also react, but the reaction is much slower.)
The reagents in this method tend to stain the test tubes. Same test tubes cannot be used since the stain would affect the absorbance reading. This method is also time sensitive. When more than one solution is tested, it is important to make sure every sample is incubated for the same amount of time for accurate comparison. [18]
Christen Thomsen Barfoed. Christen Thomsen Barfoed (16 June 1815 – 30 April 1889) was a Danish chemist credited with the development of a method to detect monosaccharide sugars in a solution, now known as the Barfoed's test. [1] [2] Barfoed is also credited with having introduced systematic chemical analyses in Danish agricultural sciences. [3]
An example of a positive Seliwanoff’s test. Seliwanoff’s test is a chemical test which distinguishes between aldose and ketose sugars. If the sugar contains a ketone group, it is a ketose. If a sugar contains an aldehyde group, it is an aldose. This test relies on the principle that, when heated, ketoses are more rapidly dehydrated than ...
Reagent test Alcohols: Forms Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. Alkaloids: Forms Froehde Liebermann Mandelin Marquis Mayer's Mecke Simon's: Amines, and amino acids: Forms Folin's: Barbiturates: Class Dille–Koppanyi Zwikker: Benzodiazepines: Class Zimmermann: Phytocannabinoids ...
Benedict's reagent (often called Benedict's qualitative solution or Benedict's solution) is a chemical reagent and complex mixture of sodium carbonate, sodium citrate, and copper(II) sulfate pentahydrate. [1] It is often used in place of Fehling's solution to detect the presence of reducing sugars and other reducing substances. [2]
Tollens' reagent tests for aldehydes (known as the silver mirror test) The Zeisel determination tests for the presence of esters or ethers; Lucas' reagent is used to distinguish between primary, secondary and tertiary alcohols. The bromine test is used to test for the presence of unsaturation and phenols.
Molisch test (using α-napthol) indicating a positive result (see purple ring). Molisch's test is a sensitive chemical test, named after Austrian botanist Hans Molisch, for the presence of carbohydrates, based on the dehydration of the carbohydrate by sulfuric acid or hydrochloric acid to produce an aldehyde, which condenses with two molecules of a phenol (usually α-naphthol, though other ...