Practice question

Ionization methods are classified by internal energy transferred to analyte during desorption process. MALDI is considered soft because organic matrix crystals absorb laser energy, buffering direct analyte irradiation and facilitating protonation with minimal excess vibrational energy deposition. Molecular ions remain largely intact, predominantly singly charged, without extensive backbone fragmentation. This preservation is crucial for measuring accurate molecular weight of labile proteins, fragile post-translational modifications, and synthetic polymers. In contrast, hard techniques like electron ionization impart high energy causing extensive fragmentation, while harsh and high-energy terms are not standard classifications for MALDI behavior.