Controlled Chemical Modification of Biomolecules by Femtosecond Laser in Polar Liquids

Covalent chemical modification of peptides and human insulin by ultrashort laser pulses in room-temperature polar liquids show highly nonlinear scaling with laser intensity. Mass spectrometry analysis of the products obtained in acetonitrile-water and methanol-water, using isotope-marked liquids, and argon sparging demonstrates the participation of dissolved oxygen and interaction of the biomolecules with the laser-modified molecules derived from the liquids.