Département de chimie moléculaire

Intramol. click-chem. is increasingly used to generate and control the architecture of complex macromols. including peptides. Such compds. are, however, very challenging to analyze, in particular quant. and also to assess their purity. In this study, tandem mass spectrometry (MS/MS) expts. were carried out with an ion trap mass spectrometer using the Survival Yield (SY) technique to analyze several mixts. of protonated, alkali and alk. earth metal complexes of two topol. linear and cyclic peptide isomers. Univariate (using a single excitation voltage) and multivariate (using several excitation voltages) calibration models have been used. The sensitivity, linearity (R2), intermediate precision (sInt) and error of predicted values (RMSEP) of external calibrations curves have been compared leading to the conclusions that: 1. quantification using tandem mass spectrometry can be performed, with very good performances, for such peptides despite isomerism, 2. quantification is also possible despite the absence of diagnostic fragment ions (possibly independently of the amino-acid sequence), 3. best results are obtained with the largest alkali cation, Cs+, while protonation is highly discouraged, 4. uni/multivariate models show similar performances, but the univariate model may be more suitable for potential applications with direct infusion by electrospray ionization (ESI-MS/MS) and/or matrix-assisted laser desorption ionization (MALDI-MS/MS). [on SciFinder(R)]