Question

Which one of the following is a correct combination of ionizer and analyser that can make a Mass Spectrometer useful to analyze biomolecules?

• A. Quadrupole(Q)-Time-of-flight (TOF)
• B. Matrix-assisted laser desorption ionization (MALDI)-Time-of-flight (TOF)
• C. Time-of-flight (TOF)
• D. Quadrupole-ion trap

Hint:

For large biomolecules, think "soft ionization." The two main soft ionization techniques are \textbf{MALDI} and Electrospray Ionization (ESI). MALDI is commonly paired with a \textbf{TOF} analyzer.

Answer 1

The Correct Option is B

Step 1: Understand the challenge. Analyzing large, fragile biomolecules (like proteins and DNA) with mass spectrometry requires "soft" ionization techniques that don't destroy the molecule, and an analyzer that can handle high mass-to-charge (m/z) ratios.

Step 2: Evaluate the options.
(1) Quadrupole(Q)-Time-of-flight (TOF): This describes a hybrid analyzer (Q-TOF), not a combination of an ionizer and analyzer.
(2) MALDI-TOF: This is a classic and highly effective combination. MALDI is a soft ionization technique where the biomolecule is co-crystallized with a matrix, which absorbs laser energy and gently transfers charge to the analyte. TOF is a mass analyzer that separates ions based on the time it takes them to fly through a tube, and it has a very high mass range, making it perfect for large biomolecules.
(3) & (4) These options list only analyzers, not the required combination of an ionizer and an analyzer.
Conclusion: MALDI-TOF is the correct combination for analyzing biomolecules.