COMPARISON OF CHARGED DERIVATIVES FOR HIGH-ENERGY COLLISION-INDUCED DISSOCIATION TANDEM MASS-SPECTROMETRY

Fixed-charge derivatives have been used to direct the fragmentation pa ttern of high energy collision-induced dissociation tandem mass spectr a for several years. It has been noted that a fixed-charge placed at a terminus of a peptide will simplify the pattern of fragment ions that are produced in collision-induced dissociation. Trimethylammoniumacet yl, dimethyloctylammoniumacetyl, and triphenylphosphoniumethyl derivat ives have been cited in the literature for this purpose and many other structures are possible. This work compares the cited derivatives as well as some new structures. The criteria used include the ease of syn thesis and purification of the derivatized peptide and the effects of the derivative on the peptide sequence fragment ion yield and ionizati on efficiency. The trimethylammoniumacetyl derivative is concluded to be the most practical for general use, whereas the dimethyloctylammoni umacetyl derivative is found to be desirable for use with hydrophilic peptides.