Sample immobilization protocols for matrix-assisted laser-desorption mass spectrometry.

Methods are described for the purification of proteins prior to analysis by matrix-assisted laser-desorption mass spectrometry. Contaminated protein samples were immobilized onto the surfaces of sample targets and rinsed. In general, a layer of electrosprayed nitrocellulose gave better results than the roughened gold surface of an untreated target. Using this approach, spectra could be obtained from low picomole quantities of protein in the presence of contaminants which did not inhibit the binding of the protein to the substrate.