RECOVERY OF PEPTIDES AND PROTEINS FOLLOWING MATRIX-ASSISTED LASER-DESORPTION IONIZATION MASS-SPECTROMETRY

Only attomole quantities of polypeptide are consumed during analysis by matrix-assisted laser desorption/ionization, despite the need to load picomole quantities of these analytes onto the target. By using radioimmunoassay we have demonstrated that the balance of the material (i.e., effectively all that was loaded onto the slide) can be recovered from the target and remains in an immunoreactive form. The bulk of the material, once recovered from the target, can be examined by other analytical techniques including sodium dodecyl sulphate polyacrylamide gel electrophoresis.