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

Turbulent Flow Chromatography: A Unique Two-Dimensional Liquid Chromatography

Among 2D-LC techniques, a particular approach is commercialized by Thermo Fisher Scientific that may enable the direct introduction of biological samples into an online automated extraction system without any additional pre-treatment: the TurboFlow technology. It combines chemical and size exclusion capability of chromatography columns packed with porous particles in which a turbulent solvent flow is able to separate smaller molecules from larger ones (e.g. proteins). Once extracted, the small molecules can also be transferred to an analytical column for improving separation prior to detection. This is done through a unique plumbing and customized valve-switching arrangement that allows the focusing of molecules onto the second column. This enables a very efficient chromatographic separation. The use of the TurboFlow not only eliminates extensive sample preparation, thus reducing inter-operator variability and matrix effects, but also increases the capacity for high-throughput analyses due to a unique multiplexing technology, in which multiple LC channels are connected to a single detector

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

Hypertonic Saline in Conjunction with High-Dose Furosemide Improves Dose–Response Curves in Worsening Refractory Congestive Heart Failure

Introduction: Diuretic responsiveness in patients with chronic heart failure (CHF) is better assessed by urine production per unit diuretic dose than by the absolute urine output or diuretic dose. Diuretic resistance arises over time when the plateau rate of sodium and water excretion is reached prior to optimal fluid elimination and may be overcome when hypertonic saline solution (HSS) is added to high doses of furosemide. Methods: Forty-two consecutively hospitalized patients with refractory CHF were randomized in a 1:1:1 ratio to furosemide doses (125 mg, 250 mg, 500 mg) so that all patients received intravenous furosemide diluted in 150 ml of normal saline (0.9%) in the first step (0–24 h) and the same furosemide dose diluted in 150 ml of HSS (1.4%) in the next step (24–48 h) as to obtain 3 groups as follows: Fourteen patients receiving 125 mg (group 1), fourteen patients receiving 250 mg (group 2), and fourteen patients receiving 500 mg (group 3) of furosemide. Urine samples of all patients were collected at 30, 60, and 90 min, and 3, 4, 5, 6, 8, and 24 h after infusion. Diuresis, sodium excretion, osmolality, and furosemide concentration were evaluated for each urine sample. Results: After randomization, 40 patients completed the study. Two patients, one in group 2 and one in group 3 dropped out. Patients in group 1 (125 mg furosemide) had a mean age of 77 ± 17 years, 43% were male, 6 (43%) had heart failure with a preserved ejection fraction (HFpEF), and 64% were in New York Heart Association (NYHA) class IV; the mean age of patients in group 2 (250 mg furosemide) was 80 ± 8.1 years, 15% were male, 5 (38%) had HFpEF, and 84% were in NYHA class IV; and the mean age of patients in group 3 (500 mg furosemide) was 73 ± 12 years, 54% were male, 6 (46%) had HFpEF, and 69% were in NYHA class IV. HSS added to furosemide increased total urine output, sodium excretion, urinary osmolality, and furosemide urine delivery in all patients and at all time points. The percentage increase was 18,14, and 14% for urine output; 29, 24, and 16% for total sodium excretion; 45, 34, and 20% for urinary osmolarity; and 27, 36, and 32% for total furosemide excretion in groups 1, 2, and 3, respectively. These findings were translated in an improvement in the furosemide dose–response curves in these patients. Conclusion: These results may serve as new pathophysiological basis for HSS use in the treatment of refractory CHF

Effect of solid waste landfill organic pollutants on groundwater in three areas of Sicily (Italy) characterized by different vulnerability

The aim of this study was to obtain information on the presence and levels of hazardous organic pollutants in groundwater located close to solid waste landfills. Eighty-two environmental contaminants, including 16 polycyclic aromatic hydrocarbons (PAHs), 20 volatile organic compounds (VOCs), 29 polychlorinated biphenyls (PCBs), 7 dioxins (polychlorinated dibenzo-p-dioxins, PCDDs) and 10 furans (polychlorinated dibenzofurans, PCDFs) were monitored in areas characterised by different geological environments surrounding three municipal solid waste landfills (Palermo, Siculiana and Ragusa) in Sicily (Italy) in three sampling campaigns. The total concentrations of the 16 PAHs were always below the legal threshold. Overall, the Fl/Fl + Py diagnostic ratio revealed that PAHs had a petrogenic origin. VOC levels, except for two notable exceptions near Palermo landfill, were always below the legal limit. As concerns PCB levels, several samples were found positive with levels exceeding the legal limits. It is worth noting that the % PCB distribution differs from that of commercial compositions. In parallel, some samples of groundwater containing PCDDs and PCDFs exceeding the legal threshold were also found. Among the 17 congeners monitored, the most abundant were the highest molecular weight ones.Published16869 – 168826V. Pericolosità vulcanica e contributi alla stima del rischioJCR Journa

Improvement of a rapid direct blood culture microbial identification protocol using MALDI-TOF MS and performance comparison with SepsiTyper kit

Fast diagnosis of pathogens is critical to guarantee the most adequate therapy for infections; bacterial culture methods, which constitute the actual gold standard, are precise and sensitive but rather slow. Today, new methods have been made available to enable faster diagnosis, with the Matrix-Assisted Laser Desorption Ionization\u2013Time Of Flight Mass Spectrometry (MALDI-TOF MS) technique being the most promising. Even if simpler and faster than traditional bacterial culture methods, analysis of positive blood cultures via MALDI-TOF MS requires a preliminary extraction process of samples. In this study, we compared two extraction protocols for bacterial identification directly from positive blood cultures using the Bruker MALDI Biotyper system (Bruker Daltonics, Billerica, MA). In particular, we evaluated the time employed and the overall performance for their accurate identification. In this work, the performances of a commercial extraction kit, named SepsiTyper\u2122 Kit, and those of the protocol developed by Treibmann et al. were evaluated and proven to be similar. However, the SELTERS method represents the best compromise price/performance. Lastly, an in-house developed analysis protocol has been tested, and the introduced optimizations granted a performance level equal if not better than the SepsiTyper kit, a reduced processing time and reduced costs