Heating temperature: 100 degree celcius
Heating time: 5 min
Standard Glucose Solution
Reagent: N-(1-Naphthyl)ethylenediamine dihydrochloride reagent in methanol solution containing 3% Sulfuric Acid
What is the fate of glucose in this reaction?
In acidic media, amine can attack at anomeric carbon, and results amino glucose. and acid promote this reaction through activating anomeric carbon.
In acidic media, amine can attack at anomeric carbon, and results amino glucose. and acid promote this reaction through activating anomeric carbon.
If the N-(1-Naphthyl)ethylenediamine dihydrochloride is not very concentrated (not equimolar with sugar), it is most likely the ocean of methanol solvent that will react with the available glucose-derived oxicarbenium intermediate. The catalytic amount of H2SO4 would here serve to do fisher esterification of the sugar resuting in methyglycoside (alpha predominant). On the other hand in the right reagent proportion (i.e. : excess of the amine, or at least equimolar with sugar), concentrations and temperature, I supect the H2SO4 would enable ring opening of sugar acetal to sugar aldehyde... The aldehyde could then ract to form an iminium that could reclose on itself to form an aminosugar whih the naphtylethylène diamine aglycon. Pretty sure you'll get mostly to exclusively the alpha anomer.
Hi Jonathan. Thank you for your answer.
I am using 6.5 mM Reagent. With this concentration, a purple-red color is observed after the completion of reaction. With an aim to maximize the intensity of produced color, I increased the concentration and carried out different experiment using concentration of 13 mM, 26 mM, 52 mM, 104 mM Reagent. But, the intensity of produced color is random. there is no linear relationship between intensity of the color observed with the concentration of the reagent.
What may be problem here?
What can we do to increase the intensity of the observed color in this reaction?
Unfortunately if the intensity of color produced is not correlating with the concentration of reagent used, a colorimetric detection method may not be appropriate for your system. What other ways could you measure concentration?
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