The UHPLC-Orbitrap-MS approach was employed for the first time to identify the phenolic compound profiling in five pomegranate genotypes. TAA was analysed using an ABTS assay, and the results showed a significant variability in nutraceutical potential of the pomegranate genotypes studied. The inclusion of phenolic information in the linear discriminant analysis allowed very good discriminations among genotypes to be obtained. © 2018 Society of Chemical Industry.

The formation and structural features of positively monocharged aggregates of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and sodium methane--(MetS), butane--(ButS) and octane--(OctS) sulfonate molecules in gas phase have been investigated by electrospray ionization mass spectrometry, energy resolved mass spectrometry and density functional theory (DFT) calculations. The experimental results show that the center-of-mass collision energy required to dissociate 50% of these monocharged aggregates scantly depends on the length of the alkyl chain as well as on the aggregation number. This, together with the large predominance of monocharged species in the mass spectra, was rationalized in terms of an aggregation pattern mainly driven by the counter ions and head groups electrostatic interactions while minor effects were attributed to the steric hindrance caused by the size of the surfactant head group and alkyl chain. DFT calculations show that the most favoured structural arrangement of these aggregates is always characterized by an internal polar core constituted by the sodium counter ions and surfactant head groups surrounded by an external layer composed by the surfactant alkyl chains.

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The phenolic profiles of six varieties of Avocado (Persea americana) grown in Sicily were investigated. The ultra-high-performance liquid chromatography- heated electrospray-mass spectrometry method was developed to determine qualitative and quantitative changes in fruits at two different ripening stage. Nineteen individual phenolic compounds were detected in avocado pulp extracts. Gallic acid, sinapinic acid, vanillin, p-coumaric acid, and gentisic acid were present only in ripe fruits. On the contrary, epicatechin decreased with fruit ripening, whereas protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, and benzoic acid were relatively stable or exhibited erratic changes with fruit ripening. The different avocado cultivars exhibited different phenolic profiles and total quantities and it was found that, among the tested cultivars, “Orotawa” avocados may provide the highest nutritional and health contribution to human diet. The qualitative and quantitative differences among cultivars and maturation stages by multivariate analysis allowed for the individuation of a set of phenolic compounds that have a great potential in the discrimination and identification of different genetic groups

In contrast with the enormous amount of literature produced during many decades in the field of surfactant aggregation in liquid, liquid crystalline and solid phases, only a few investigations concerning surfactant self- assembling in the gas phase as charged aggregates have been carried out until now. This lack of interest is disappointing in view of the remarkable theoretical and practical importance of the inherent knowledge. The absence of surfactant-solvent interactions makes it easier to study the role of surfactant-surfactant forces in determining their peculiar self-assembling features as well as the ability of these assemblies to incorporate selected solubilizate molecules. Thus, the study of gas-phase surfactant and surfactant-solubilizate aggregates is a research subject which has exciting potential, including mass and energy transport in the atmosphere, origin of life and simulation of supramolecular aggregation in interstellar space. On the other hand, the structural and dynamic properties of surfactant aggregates in the gas phase could be exploited in a number of interesting applications such as atmospheric cleaning agents, transport and protection of pulmonary drugs or biomolecules and as nanoreactors for specialized chemical reactions in confined space. Spectrometric techniques, together with molecular dynamics simulations, have been the principal investigative tools in this field and appearto be particularly suited to gaining fundamental information on the structure and stability of surfactant-based supramolecular aggregates, charge state effects, entrapment of solubilizate molecules, preferential solubilization sites and chemical reactions localized in a single organized aggregate. The main aim of this review is to present the actual state of the art in this novel and exciting research field underlining the knowledge acquired up to now as well as the aspects needing a more deep understanding. Moreover, intriguing departures of the behavior of surfactant solutions under electrospray ionization conditions from that of ionic, polar and apolar analytes will be discussed.

Self-assembling of amphiphilic molecules under electrospray ionization (ESI) conditions is characterized by quite unexpected phenomenology. The noticeable differences with respect to the condensed phase are attributable to the absence of the surfactant-solvent interactions, the presence of net charge in the aggregates, and the strong deviation from equilibrium conditions. Aiming to investigate the effects of the net charge on abundance and stability of supramolecular surfactant aggregates, positively and negatively charged aggregates of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium methane sulfonate (MetS), butane sulfonate (ButS) and octane sulfonate (OctS) have been studied by ESI mass spectrometry, energy resolved mass spectrometry and density functional theory calculations. The negatively charged aggregates are found to be less stable than their positive counterparts. The results are consistent with a self-assembling pattern dominated by electrostatic interactions involving the counterions and head groups of the investigated amphiphilic compounds while the alkyl chains point outwards, protecting the aggregates from unlimited growth processes.

One important feature in the gas phase chemistry of surfactants is to ascertain whether their aggregates produced by electrospray ionization reflect those formed in the starting solution. With this aim, we have performed ESI-MS, ESI-MS/MS and ER-MS spectra of bis(2-ethylhexyl)sulfosuccinate (AOTNa) solutions in different solvents, i.e. water, water/methanol, methanol and n-hexane. The results clearly indicate that, notwithstanding the strongly different aggregation state in solution (direct micelles in water and in water/methanol, molecular dispersion in methanol and reverse micelles in n-hexane) and marked effects of the solvent polarity on the total ionic current, the surfactant aggregates in gas phase show identical structural features. Analogous conclusions can be drawn analyzing the infrared multiple photon dissociation (IRMPD) spectra of AOTNa solutions in water/methanol and n-hexane. Moreover, according to the idea that gas phase can be considered an apolar environment par excellence, data consistently suggest a reverse micelle-like aggregation. Some peculiarities of the mechanisms leading to aggregate formation through electrospray ionization of surfactant solutions in solvent media with different polarity have been also discussed.

A large number of certified samples (84) of Sicilian olive oils arising from the eight cultivars most represented in Sicily (Biancolilla, Cerasuola, Moresca, Nocellara del Belice, Nocellara Etnea, Oglialora Messinese, Brandofino and Tonda Iblea) have been collected and analyzed by HPLC/MS using an atmospheric pressure chemical ionization (APCI) source. The sample preparation is very simple; in fact, the oil samples are diluted without any chemical derivatization. A following statistical data treatment by general discriminant analysis (GDA) allows the determination of the olive oil cultivar. Furthermore, changes in the composition of glyceridic components of the olive oils lead to easy discrimination between fresh oils and 1-year-old samples.