In the condensation method, what color indicates formation of Schiff's base with glucose?

In the condensation method, what color indicates formation of Schiff's base with glucose?

• A. Green
• B. Red
• C. Blue
• D. Yellow

Answer: (A)

In this condensation method, the key signal is the formation of a Schiff base, which occurs when the aldehyde group of glucose reacts with an amino-containing reagent to form an imine linkage. The specific chromophore produced by this reaction in the assay yields a green color. So, seeing green indicates that the Schiff base has formed, signaling a positive result for glucose under these conditions. If no Schiff base forms, or if a different reaction dominates, the color would be different or absent, not green. The open-chain aldehyde form of glucose is present enough in the test conditions to drive this condensation and produce the green color, with the color intensity relating to the amount of glucose present.

In this condensation method, the key signal is the formation of a Schiff base, which occurs when the aldehyde group of glucose reacts with an amino-containing reagent to form an imine linkage. The specific chromophore produced by this reaction in the assay yields a green color. So, seeing green indicates that the Schiff base has formed, signaling a positive result for glucose under these conditions. If no Schiff base forms, or if a different reaction dominates, the color would be different or absent, not green. The open-chain aldehyde form of glucose is present enough in the test conditions to drive this condensation and produce the green color, with the color intensity relating to the amount of glucose present.