Synthesis and MS Analysis of Thiazolium and Pyridinium Derivatives of Peptide Nucleic Acids (PNAs) and Peptides

Sensitivity of ESI-MS analysis of crude PNAs is enhanced using their pyridinium or thiazolium derivatives. Identification of the molecular ion of the product is easier when the label contains bromine, based on the isotope distribution. Study of side reactions, occurred upon the synthesis and/or cleavage, is simple with labelling. Sequencing of non-polar peptides is clear as only a(n) type ions can be observed during their MS/MS analysis.