Fehlings Solution No.1 Blue 1L
23508-1L

  DG9 Enviro toxin

Fehlings Solution No.1 (also called Fehlings A)

Code 53508

BLUE solution - Contains CuSO4

For the determination of reducing sugar in conjunction with Fehlings Solution No 2.

U.N Number 3082 ; DG Class 9 Enviro toxic ; Packing Group III (very low risk)

 

 

Fehling's test is a chemical analysis used to detect reducing sugars* eg glucose . 

To use:-

Fehlings No.1 [or A])-a  Blue alkaline solution of copper(II) sulfate

Fehlings No.2 [or B]) - a clear(or water white)solution of  potassium sodium tartrate in sodium hydroxide 

Mix equal parts of No1 (blue) and No2 (clear)

Add to the sample ( use the test solutions in proportion to the sample - so don't overwhelm a small sample with a large amount of test solution ) and heat in a water bath

If there is a brick red precipitate ( Copper(I) oxide) then a reducing sugar is present . No colour change, no reducing sugar..

Principle:  The aldehyde group is oxidized to a carboxylate ion, while the copper(II) tartrate complex is reduced to insoluble copper(I) oxide (red precipitate).

Reducing sugars - these have an aldehyde group - Main  examples -  glucose, fructose, galactose ie all monosaccharides and some disaccharides (lactose, maltose)

Notable exceptions - Sucrose( "sugar")

The net reaction between an aldehyde and the copper(II) ions in Fehling's solution may be written as: RCHO + 2Cu2+ ( copper(II) ions blue in colour) +5OH− ⟶ RCOO−  + Cu2O (Copper(I) oxide red in colour )+3H2O

Where R is the alkyl chain and CHO is the aldehyde "tail" and COO the carboxylate group

Unit Qty: ea

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