Solvent-free mass spectrometry for hydrophobic peptide sequence analysis and protein conformation studies.

The breakthrough in soft ionization methods for biopolymers, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) (1,2), revolutionized mass spectrometry (MS). As a result of these effective bioanalytical technologies, the entire field of proteomics changed, and the use of mass spectrometers for protein identification by accurate mass measurements or de novo sequencing of the corresponding proteolytic peptides is now universally accepted. Bioanalytical techniques ideally aim for a maximum degree of unbiased analytical information hence, simplification of these techniques can become both more efficient and often more reliable. Such is the case with a new approach in the use of MALDI-MS.