MATRIX-ASSISTED UV LASER-DESORPTION OF BIOPOLYMERS - INFLUENCE OF THEINTERACTIONS IN THE TARGET

The influence of the nature of the matrix and of the macroscopic struc ture of the target on the MALD spectra of proteins has been systematic ally studied for matrices such as 2,5-dihydroxybenzoic acid, 3,5-dimet hoxy-4-hydroxycinnamic acid, 3-hydroxy-4-methoxycinnamic acid and alph a-cyano-4-hydroxycinnamic acid. Only 3,5-dimethoxy-4-hydroxycinnamic h as been found to give homogeneous targets and reproducible spectra. Th e neutral contribution to the protein molecular and cluster peaks, whi ch depends on the the laser fluence and on the mass of the protein, al so strongly depends on the nature of the matrix.