Biuret Test for Proteins
The Biuret test uses copper sulphate and sodium hydroxide to detect protein.
What colour change indicates a positive result?
What is Biuret Test for Proteins?
"The biuret test is a chemical test used for detecting the presence of peptide bonds (proteins)."
What colour change shows starch is present when iodine solution is added?
Which result would show protein is present?
A food sample gives a brick-red precipitate with Benedict’s solution after heating. What does this show?
Which observation is a positive result for the emulsion test for lipids?
Testing for Proteins
Add Biuret reagent (or NaOH then CuSO4) to the sample.
Shake gently and wait for a few minutes.
Positive result: colour change from blue to purple/lilac.
Biuret reagent is corrosive; handle with care and wear eye protection.
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