Question

Hich possible errors did you include in your response? Check all that apply.

The water should not be pink/purple because water should test negative for protein.

The water should actually have turned blue, because Biuret solution is blue.

Someone may have mislabeled the test tube with water

The water may have been contaminated with a protein.

Answer 1

Step-by-step explanation:

analyte contributes to the intensity of the purple colour. Short-chain peptides often yield blue or pink colours in the biuret test.

Biuret Test Procedure

The procedure that can be followed to conduct a biuret test is provided below.

An aqueous solution of the analyte must be prepared by dissolving it in water.

A small amount of this aqueous solution must be treated with 1% sodium hydroxide or potassium hydroxide. To this mixture, a few drops of CuSO4 (aq) must be added.

If the solution turns purple upon the addition of copper(II) sulphate, the presence of protein in the analyte is confirmed.