Question

Which of the following is not true about the guard column used in liquid chromatography?

• A. It filters particles that clog the separation column
• B. It extends the life time of separation column
• C. It allows particles that cause precipitation upon contact with stationary or mobile phase
• D. The size of packing varies with the type of protection needed

Answer 1

The Correct Option is C

Step 1: Understanding the Role of a Guard Column - A guard column is used in liquid chromatography to protect the analytical column from contaminants, particulate matter, and strongly retained compounds. - It is usually a short column packed with similar stationary phase material as the main column.


Step 2: Evaluating the Options - (A) It filters particles that clog the separation column → True. The guard column acts as a protective barrier against contaminants.
- (B) It extends the life time of separation column → True. By preventing contamination, it increases the longevity of the analytical column.
- (C) It allows particles that cause precipitation upon contact with stationary or mobile phase → False. The guard column is specifically designed to prevent such particles from reaching the main column.
- (D) The size of packing varies with the type of protection needed → True. Depending on the sample and type of contamination, different packing sizes can be used.


Step 3: Selecting the Correct Answer - Since a guard column does not allow particles that cause precipitation, option (C) is incorrect and is the right answer.