INVESTIGATION OF PORPHYRINS AND METALLOPORPHYRINS BY LIQUID MATRIX-ASSISTED LASER-DESORPTION MASS-SPECTROMETRY

Laser desorption mass spectrometry with liquid matrix-assistance has b een used to study a series of selected porphyrins and metalloporphyrin s. This work presents the results of using a liquid matrix with fibrou s material as the substrate for liquid matrix assisted laser desorptio n of porphyrins and metalloporphyrins. The liquid matrices used for po rphyrin studies were o-nitrophenyl octyl ether (NPOE) and 15-crown-5. The use of a liquid matrix with soft laser ionization enhances molecul ar ion formation. We also have investigated the use of NPOE as a liqui d matrix for identifying mixtures of up to six porphyrins in a single shot spectrum without prior separation. The (M + H)+ peak of each meta lloporphyrin component in the mixture is clearly indicated in the spec tra and no obvious interference effects were observed.