Nives Galić
University of Zagreb, Croatia
Title: Structural investigation of organic compounds and their complexes by ESI MS/MS
Biography
Biography: Nives Galić
Abstract
The application of electrospray tandem mass spectrometry (ESI MS/MS) in organic analysis, as well as in pharmaceutical industry, will be presented and discussed on several examples as follows:
1. Structural isomers of aromatic hydrazones derived from nicotinic acid hydrazide were identified due to comprehensive study of their fragmentation pathways. Isomers derived from 3- and 4-hydroxy salicylaldehyde, as well as those derived from 3- and 5-chloro salicylaldehyde were distinguished due to "ortho effect". The MS/MS spectra and fragmentation pathways of compounds derived from 3- and 4-methoxy salicylaldehyde differ due to enolimino-ketoamino tautomeric interconversion of one isomer.
2. Peptidocalixarenes bearing tryptophan, phenylglycine and leucine at the lower rim and their complexes with alkali-metal (Li+, Na+, K+, Rb+, Cs+) and selected lanthanide cations (La3+, Ce3+, Eu3+, Yb3+) were analyzed by ESI MS/MS. The results of MS analysis were in accordance with those obtained by other techniques (spectrophotometric, potentiometric, and conductometric titrations). The MS/MS experiments could be used as fast and sensitive method for prediction of relative stabilities of calixarene complexes with metal ions.
3. Bivalirudin, a synthetic oligopeptide, is used as anticoagulant for patients with acute coronary syndromes or patients undergoing percutaneous coronary intervention. Forced degradation studies were performed using acid, base, H2O2, heat and light exposure as recommended by the International Conference on Harmonization (ICH). An UPLC method with UV detection for determination of bivalirudin in the presence of its degradation products has been developed. However, for the identification of degradation products the 2D LC MS/MS system had to be used.