Ricerc@Sapienza

5-hydroxymethylfuraldehyde (5-HMF) is the main product of the thermal acid-catalysed dehydration of monosaccharides and together with other furan compounds is considered a platform molecule for the production of chemicals and fuels. Identifying alternative catalytic strategies to synthesize 5-HMF represents a key-step to increase reaction selectivity and reduce degradation-by-product yields. In this regard, mass spectrometry has proved to be an useful tool for studying reaction mechanisms in absence of solvent molecules.

The gas-phase reactivity of doubly-charged vanadium hydroxides anions with SO2 has been studied by experimental and computational methods. The obtainedresults highlight the role of sulfur dioxide in promoting unprecedented bond-forming reactions, which produce singly-charged products by breaking the VxOy skeleton or a terminal VObond.

The primary complex obtained from cisplatin and l-histidine in water has been detected and isolated by electrospray ionization. The so-obtained cis-[PtCl(NH3)2(histidine)]+ complex has been characterized in detail by high-resolution mass spectrometry (MS), tandem MS, IR multiple photon dissociation (IRMPD) spectroscopy, and by quantum chemical calculations. The structural features revealed by IRMPD spectroscopy indicate

The gas-phase structure of protonated β-methylaminoalanine was investigated using infrared multiple photon dissociation spectroscopy in the C-H, N-H, O-H stretching region (2700-3800 cm-1) and the fingerprint region (1000-1900 cm-1). Calculations using density functional theory methods show that the lowest energy structures prefer protonation of the secondary amine. Formation of hydrogen bonds between the primary and secondary amine, and the secondary amine and carboxylic oxygen further stabilize the lowest energy structure.

Short peptides are important compounds in a variety of fields, including food and nutraceutical applications, but also biomarker discovery, bioactive peptide discovery and peptide drug separation. Despite the importance of short peptides, they are currently less studied than other peptides because of the lack of dedicated methods for their characterization. The method described in this paper comprises a combination of strategies to tackle the main limitations in short peptide analysis.

An analytical method for determining seleno-methionine, methyl-seleno-cysteine, and seleno-cystine in wheat bran was developed and validated. Four different extraction procedures were evaluated to simultaneously extract endogenous free and conjugated seleno-amino acids in wheat bran in order to select the best extraction protocol in terms of seleno amino acid quantitation. The extracted samples were subjected to a clean-up by a reversed phase/strong cation exchange solid-phase extraction and analyzed by chiral hydrophilic interaction liquid chromatography-tandem mass spectrometry.

The combination of an efficient chromatographic separation with post-column addition of a supercharging agent was evaluated for the determination of small peptides. The procedure takes advantage of porous graphitic carbon (PGC) ability in retaining very polar and ionic molecules to overstep the poor retention of small peptides on conventional reversed phase (RP) columns. The method was developed specifically for the most hydrophilic di-, tri- and tetrapeptides, which are not identified in ordinary peptidomics experiments.

An analytical method for determining seleno-methionine (SeMet), methyl-seleno-cysteine and seleno-cystine in extra-virgin olive oil (EVOO) was developed and validated. EVOO sample (15 g) was diluted with hexane, extracted with methanol/water 80:20 (v/v), and cleaned up by a reversed phase/strong cation exchange solid phase extraction. Analysis was performed by chiral hydrophilic interaction liquid chromatography-tandem mass spectrometry.

This chapter offers a concise overview on conventional methods and on the latest advancements in liquid chromatography analysis of water-soluble and fat-soluble vitamins. Since there are a significant variety of biologically active forms and matrices of interest, some recent techniques, instruments and approaches have been considered due to their importance in solving complex separations of vitamin homologues as well as comprehensive profiling of organic micronutrients in biological samples.

Photoionization mass spectrometry, photoelectron-photoion coincidence spectroscopic technique, and computational methods have been combined to investigate the fragmentation of two nitroimidazole derived compounds: the metronidazole and misonidazole. These molecules are used in radiotherapy thanks to their capability to sensitize hypoxic tumor cells to radiation by "mimicking" the effects of the presence of oxygen as a damaging agent.