Endothermic ion/molecule reactions III. High energy collisional activation at low kinetic energies

Endothermic reactions between leucine enkephalin and ammonia have been carried out at very low beam energies, and compared with activation obtained by conventional collision‐induced dissociation at both low and high energies. The similarity between the high‐energy and the reactive‐collisions spectra suggest that comparable energies are imparted by these two methods. The upper limit of the collision energy deposited by reactive collisions is only 0.30 eV. In addition, a substantial increase in the collection efficiency is observed with endothermic reactions, with the sum of the fragment ions exceeding the intensity of the surviving parent ions.