Degrees of freedom effect on fragmentation in tandem mass spectrometry of singly charged supramolecular aggregates of sodium sulfonates

The characteristic collision energy (CCE) to obtain 50% fragmentation of positively and negatively single charged non-covalent clusters has been measured. CCE was found to increase linearly with the degrees of freedom (DoF) of the precursor ion, analogously to that observed for synthetic polymers. This suggests that fragmentation behavior (e.g. energy randomization) in covalent molecules and clusters are similar. Analysis of the slope of CCE with molecular size (DoF) indicates that activation energy of fragmentation of these clusters (loss of a monomer unit) is similar to that of the lowest energy fragmentation of protonated leucine-enkephalin. Positively and negatively charged aggregates behave similarly, but the slope of the CCE vs DoF plot is steeper for positive ions, suggesting that these are more stable than their negative counterparts

Multiple points of view of heteronuclear NOE: long range vs short range contacts in pyrrolidinium based ionic liquids in the presence of Li salts.

The nuclear Overhauser enhancement (NOE) is a powerful tool of NMR Spectroscopy extensively used to gain structural information in ionic liquids (ILs). A general model for the distance dependence of intermolecular NOE in ILs was recently proposed showing that NOE spots beyond the first solvation shell and accounts for long-range effects. This conclusion prompted for a deep rethinking of the NOE data interpretation in ILs. In this paper we present an extensive and quantitative study of N-propyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI), the homologue with bis(fluorosulfonyl)imide (PYR13FSI), and their mixtures with LiTFSI based on {1H-19F} and {1H-7Li}NOE correlation experiments (HOESY). The former is mainly tuned on long-range interactions, the latter on short-range ones, due to the small and large Larmor frequency differences of the involved nuclei. The collected data are discussed in two different way: long-range {1H-19F}NOEs spot on the polar/apolar domains within the ILs, whereas short-range (e.g. regarding the first coordination shell) {1H-7Li}NOEs describe the contacts between first neighbors, with interesting correlation with the distances’ statistics derived by crystallographic data of related systems

Quantitative evaluation of the phenolic profile in fruits of six avocado (Persea americana) cultivars by ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry

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

Genotoxicity of citrus wastewater in prokaryotic and eukaryotic cells and efficiency of heterogeneous photocatalysis by TiO2

The presence of (±)a-pinene, (+)b-pinene, (+)3-carene, and R-(+)limonene terpenes in wastewater of a citrus transformation factory was detected and analyzed, in a previous study, by using Solid Phase Microextraction (SPME) followed by GC analyses. Purpose of that research was to compare the genotoxic responses of mixtures of terpenes with the genotoxicity of the individual compounds, and the biological effects of actual wastewater. Genotoxicity was evaluated in the Salmonella reversion assay (Ames test) and in V79 cells by Comet assay. Ames tests indicated that the four single terpenes did not induce an increase of revertants frequency. On the contrary, the mixtures of terpenes caused, in the presence of metabolic activation, a highly significant increase of the revertants in TA100 strain in comparison to the control. The Comet assay showed a significant increase in DNA damage in V79 cells treated for 1 h with single or mixed terpenes. Moreover, the actual wastewater was found highly genotoxic in bacterial and mammalian cells. Photocatalytic tests completely photodegraded the pollutants present in aqueous wastewater and the initial high genotoxicity of samples of wastewater collected during the photocatalytic run, was completely lose in 3 h of irradiation

The ascidian Styela plicata hemocytes as a potential biomarker of marine pollution: In vitro effects of seawater and organic mercury

Toxic metals, such as mercury, contribute substantially to anthropogenic pollution in many estuarine environments. Animals living in those environments, particularly invertebrate filter feeders like tunicates, can be used as bioindicators. In an attempt to identify cellular markers for revealing pollution, this study examined in vitro the effects of different concentrations of methyl mercury on Styela plicata hemocytes. The harvested hemocytes from S. plicata that were exposed to the metal had a significant mortality, cellular count and morphometric alterations. These findings provided evidence of MeHg immunotoxic effects on S. plicata, resulting in hemocyte death and morphological changes induced by cytoskeleton alterations. Thus, a morphometric cellular parameter, such as spreading ability, was used as a complementary method for differentiation between hemocytes treated with a marine solution (as a negative control) and hemocytes incubated with methylmercury and/or Sicilian seawater samples

ION MOBILITY STUDIES ON SODIUM-BIS (2- ETHYLHEXIL)SULFOSUCCINATE (AOTNa) AGGREGATES

The supramolecular charged aggregates formed during ESI ionization of AOTNa solutions under critical micelle concentration have been studied thorough ion mobility experiments. In particular, positively charged clusters with several charge states, ranging from +1 to +4, have been investigated. It has been found that, despite to previous investigations (Siuzdak et al. 1995, Nohara et al. 1998), specific ionic aggregates with a peculiar cross section are observed. Indeed a single drift time is observed for each charged aggregate. Using both calculated cross section and experimental calibration curves the experimental cross section of the observed cation has been determined. It is worth noting that simulated reversed micelle structure (through mobcal EHSS algorithm) cross section and experimental ones air in fair agreement. This agreement is a further support that reverse micelle is the most likely structure that characterize such aggregates

NEW INSIGHTS ON SUPRAMOLECULAR AGGREGATES OF SODIUM DOCUSATE (AOTNa) BY ION MOBILITY MASS SPECTROMETRY

Backgorund: The ability of some surfactants to form charged aggregates in gas phase has been proven experimentally by electrospray ionization (ESI) spectrometry [1- 5]. However, in the early investigations, interesting questions concerning the structural organization of these aggregates in gas phase and if they reflect their typical self-assembling in the starting liquid solutions were not addressed. Subsequently, independently of their aggregation motive in liquid phase and of the charge state in the gas phase, some hints suggesting that surfactant molecules are organized in gas phase as reverse micelle-like aggregates have been reported Objective: The supramolecular charged aggregates formed by ESI of AOTNa solutions have been studied through ion mobility experiments in order to gain more informations as concer their size, and possibly, shape. Method: AOTNa (99%) was purchased from Sigma-Aldrich-Fluka (Milan, Italy). For ion mobility experiments, a 2.4 mg/ml AOTNa solution in a 1:1 water/acetonitrile mixture was prepared and directly infused at a flow rate 10 l/ min in positive mode electrospray. The ESI mass spectra are recorded under following operative conditions: source temperature 120 °C, capillary voltage 3 kV, cone voltage 45 V, extraction cone 4.0 V, Desolvation Temperature 350 °C, Cone Gas Flow 10.0 L/Hr, Desolvation Gas Flow 800.0 L/Hr. The ion mobility cell contained nitrogen at a flow rate of 90 ml/min. The travelling wave height and velocity were 6 V and 311 m/s respectively. Under the same experimental conditions, solutions of polyalanine (Sigma, nominal 1000-5000 mol wt range; 5.6*10-5 to 2.8*10-4 M in a 49:49:2 water/acetonitrile/acetic acid mixture) were also infused. The samples were analyzed by a Synapt G2 HDMS (Waters UK Ltd, Manchester, UK) and data were acquired by MassLynxTM version 4.1 in high-definition mass spectrometry (HDMS) mode and handled by DriftScope. Results and conclusion: Positively charged clusters with several charge states, ranging from +1 to +4, have been investigated. Despite of previous investigations (Siuzdak et al. 1995, Nohara et al. 1998), suggesting random aggregation of charged surfactant aggregates, specific ionic clusters with peculiar cross sections are observed. Indeed the occurrence at each aggregation number and extra charge of an unique value of cross section points toward aggregates whose conformations do not show discernible shape change in the experiment time scale. It is worth noting that calculated cross-sections (mobcal EHSS algorithm, considering reversed micelle structures) and experimental ones (through ion mobility mass spectrometry using Polyalanine at various charge states as reference) are in fair agreement. This supports once again that reverse micelle is the most likely structure that characterize such aggregates. Further this allows evaluating of the charge state effects on the shape of AOTNa clusters. In particular, both theoretical calculations and experimental CCS suggest an increase of the size of the whole aggregate on increasing the charge states. Finally, the regular cross section dependence on the aggregation number of AOTNa clusters at the same charge state makes this surfactant an ideal candidate as calibration standard for CCS measurements

Effects of the net charge on abundance and stability of supramolecular surfactant aggregates in gas phase

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

Helix aspersa aspersa flour: An evaluation for dietary supplementation

This study assesses the nutritional composition and safety of lab-produced snail flour derived from Helix aspersa aspersa, an herbivorous pulmonated gastropod mollusc that occupies various trophic levels in food chains. Our analysis focused on key nutritional aspects, including moisture, ash, protein, and fat contents. Contaminant analysis on the powder showed levels below detectable limits for PAHs, PCBs, PBDEs. The heavy metal concentration was found to be either on par with or lower than values reported in existing literature, indicating the safety of these snail powders for human consumption. Our results revealed a notable presence of polyunsaturated fatty acids and essential amino acids and strongly support the idea that snail powders can serve as sustainable protein sources in both human and animal diets

HPLC/HRMS and GC/MS for Triacylglycerols Characterization of Tuna Fish Oils Obtained from Green Extraction

Background: Fish oil is one of the most common lipidic substances that is consumed as a dietary supplement. The high omega-3 fatty acid content in fish oil is responsible for its numerous health benefits. Fish species such as mackerel, herring, tuna, and salmon are particularly rich in these lipids, which contain two essential omega-3 fatty acids, known as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Objectives: Due to the scarcity of information in the literature, this study aimed to conduct a qualitative and quantitative characterization of triglycerides (TAGs) in crude tuna fish oil using HPLC/HRMS. Fatty acid (FA) determination was also performed using GC/MS. The tuna fish oils analyzed were produced using a green, low-temperature process from the remnants of fish production, avoiding the use of any extraction solvents. Results: The analyses led to the tentative identification and semi-quantitation of 81 TAGs. In silico saponification and comparison with fatty acid methyl ester results helped to confirm the identified TAGs and their quantities. The study found that the produced oil is rich in EPA, DHA, and erucic acid, while the negligible isomerization of fatty acids to trans-derivatives was observed