Which analytical technique involves fragmentation and ionization of molecules for analysis?

• A. Nuclear magnetic resonance
• B. Ultraviolet-visible spectroscopy
• C. Mass spectrometry
• D. Infrared spectroscopy

Answer: (C)

Mass spectrometry is the technique where molecules are converted into charged particles and then analyzed based on their mass-to-charge ratio. The ionization step creates ions, and in many ionization processes the molecules also break into fragments. This combination—turning molecules into ions and often fragmenting them—produces a spectrum that reveals the molecular weight of the analyte and a pattern of fragments that helps deduce structural information. This fragmentation and ionization approach distinguishes it from the other methods: NMR relies on magnetic properties of atomic nuclei, UV-Vis tracks electronic transitions without breaking molecules, and IR measures vibrational modes through infrared absorption without generating a family of charged fragments for analysis.