ABSTRACT
MS is considerably more sensitive than any other conventional techniques, but the need for previous cleavage restricted its development. Chávez et al. (2003) developed a simple method based on mass spectrometry direct-insertion and a quadrupole detector. They set the instrument’s isothermal rate at 325°C and the high-temperature and vacuum-promoted thermal cleavage on the benzylic position. Once the molecules attached to the bead were liberated, the mass spectrum could be obtained in full
scan mode with the normal technique of electron impact ionization and a quadrupole detector
When synthesized on a photolabile linker (such as α-methylphenacylester linker and 3-amino-3-(2-nitrophenyl) propionyl linker), a compound can be cleaved with a UV laser beam (e.g., ~337 nm) at any time during the synthesis. The released fraction of the compound can be analyzed by any conventional methods. Photocleavage combined with the MALDI-MS analysis using 1-50 beads has been used to monitor reactions (Fitzgerald et al. 1996).
