Antioxidant activity of Zuccagnia-type propolis: A combined approach based on LC-HRMS analysis of bioanalytical-guided fractions and computational investigation.

This study reports a combined approach to assess the antioxidant activity of Zuccagnia-type propolis. Fractions exhibiting the highest antioxidant activities evidenced by DPPH, a β-carotene bleaching and superoxide radical scavenging activity-non-enzymatic assays, were processed by LC-HRMS/MS to characterize the relevant chemical compounds. A computational protocol based on the DFT calculations was used to rationalize the main outcomes.

Intestinal Absorption Study of a Granular Form of Ferric Pyrophosphate.

Iron deficiency is one of the most prevalent nutritional disorders worldwide. The standard treatment involves iron supplementation, but this task is challenging because of poor solubility and organoleptic issues. Moreover, the need to increase iron bioavailability represents a challenge for treating iron-related disorders.

New insights in the slow ligand exchange reaction between Cr(III)-EDTA and Fe(III), and direct analysis of free and complexed EDTA in tannery wastewaters by liquid chromatography - Tandem mass spectrometry.

EDTA and soluble Cr(III) are usually both present in wastewaters coming from treatment plants handling tannery effluents. A well-established method to determine EDTA is based on the conversion of free and complexed EDTA into its Fe(III) complex. This procedure gives inconsistent data when Cr(III)-EDTA is present.

Biocontrol traits of Bacillus licheniformis GL174, a culturable endophyte of Vitis vinifera cv. Glera.

Background: Bacillus licheniformis GL174 is a culturable endophytic strain isolated from Vitis vinifera cultivar Glera, the grapevine mainly cultivated for the Prosecco wine production. This strain was previously demonstrated to possess some specific plant growth promoting traits but its endophytic attitude and its role in biocontrol was only partially explored. In this study, the potential biocontrol action of the strain was investigated in vitro and in vivo and, by genome sequence analyses, putative functions involved in biocontrol and plant-bacteria interaction were assessed.

Liquid chromatography-high resolution mass spectrometric methods for the surveillance monitoring of cyanotoxins in freshwaters.

A comprehensive risk management on human exposure to cyanotoxins, whose production is actually unpredictable, is limited by reliable analytical tools for monitoring as many toxic algal metabolites as possible. Two analytical approaches based on a LC-QTOF system for target analysis and suspect screening of cyanotoxins in freshwater were presented. A database with 369 compounds belonging to cyanobacterial metabolites was developed and used for a retrospective data analysis based on high resolution mass spectrometry (HRMS).

Characterization of lipopeptides produced by Bacillus licheniformis using liquid chromatography with accurate tandem mass spectrometry.

Rationale: The plant endophyte Bacillus licheniformis, isolated from leaves of Vitis vinifera, was studied to individuate and characterize the presence of bioactive lipopeptides having amino acidic structures.

Methods: Crude extracts of liquid cultures were analyzed by ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole time-of-flight (QTOF) mass analyzer. Chromatographic conditions were optimized in order to obtain an efficient separation of the different isobaric lipopeptides, avoiding merged fragmentations of co-eluted isomeric compounds and reducing possible cross-talk phenomena.

Characterization and quantification of N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine biocide by NMR, HPLC/MS and titration techniques.

The present paper reports the determination of the tri-amine N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) present in a raw material called LONZABAC used to formulate various, widely used commercial biocides. The active principle, TA, is present in LONZABAC together with other molecules at lower concentration levels. Three independent analytical approaches, namely solution NMR spectroscopy, liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) and acid-base titration in mixed solvent, were used to overcome the problem of the non-availability of the active principle as high purity standard.

Degradation products from naturally aged paper leaves of a 16th-century-printed book: a spectrochemical study.

In this work, we present a wide-range spectrochemical analysis of the degradation products from naturally aged paper. The samples obtained from wash waters used during the de-acidification treatment of leaves from a 16th-century-printed book were analysed through NMR, IR, Raman UV/Vis, EPR and X-ray fluorescence (XRF) spectroscopy and HPLC-MS and inductively coupled plasma (ICP) analysis. By these methods we also studied some of the previous samples treated by acidification (sample AP) and catalytic hydrogenation (sample HP).

Application of LC-MS and LC-MS-MS to the analysis of photo-decomposed crystal violet in the investigation of cultural heritage materials aging.

In this work, the accurate liquid chromatography-ultraviolet-visible (LC-UV-Vis), LC-mass spectrometry (MS) and LC-MS-MS analysis of the photo-degradation products of crystal violet (CV) is reported. CV is a light fugitive early synthetic dye which had a widespread diffusion into the market starting from the end of the XIX century and was used among others by V. Van Gogh and P.

The mystery of the discolored flints. New molecules turn prehistoric lithic artifacts blue.

Prehistoric artifacts turning blue in the store rooms of the Natural History Museum in Verona, Italy recently raised serious issues for heritage materials conservation. Our analytical investigation showed that the unusual discoloration process of the flint tools is caused by the surface presence of at least three previously unknown pigmenting molecules of the triphenylmetane dyes class: 6-(bis(2,2,4-trimethyl-1,2-dihydroquinolin-6-yl)methylene)-2,2,4-trimethyl-2,6-dihydroquinolinium and its hydrogenated derivatives 2,2,4-trimethyl-6-((2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl)(2,2,4-trimethyl-1,2-dihydroquinolin-6-yl)methylene)-2,6-dihydroquinolinium and 6-(bis(2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl)methylene)-2,2,4-trimethyl-2,6-dihydroquinolinium. The peculiar formation of the molecules is possibly catalyzed within the silica pore surface starting from a well-known rubber stabilizer 2,2,4-trimethyl-1,2-dihydroquinoline released by the plastic pads flooring the storing cabinets.

Helicobacter pylori acidic stress response factor HP1286 is a YceI homolog with new binding specificity.

HP1286 from Helicobacter pylori is among the proteins that play a relevant role in bacterial colonization and persistence in the stomach. Indeed, it was demonstrated to be overexpressed under acidic stress conditions, together with other essential virulence factors. Here we describe its crystal structure, determined at 2.

Evidence of Cr(VI) formation during analysis of leather Proposal of an alternative method of analysis through the ion-chromatographic approach and post-column reaction.

The formation of Cr(VI) in Cr(III) tanned leather, in neutral and alkaline solution, has been demonstrated by means of crossed experiments using different pH buffers, ethylenediaminetetraacetic acid as Cr(III) complexing agent and NaCl solutions. According to the found results the composition of the extracting solution suitable to extract Cr(VI) amount present in leather was pH 4.4 (which is also the tanned leather natural pH) and 5% NaCl (w/v).

Quantitative determination of chlorophenols in leather by pressurized liquid extraction and liquid chromatography with diode-array detection.

Pressurized liquid extraction (PLE) with acetonitrile was used for the recovery of chlorophenols (4-chloro-3-methylphenol, 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2-phenylphenol, 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol) present as biocides in leather. After a single cycle PLE treatment, solutions underwent pre-concentration by evaporation of the solvent under vacuum and clean-up treatment with solid-phase extraction cartridges. Quantitative analysis of the target compounds was carried out by liquid chromatography with gradient elution and UV spectrophotometric detection at variable wavelength for the various analytes in the range 190-240 nm.

A pH-stat study of the reaction of some transition metal cations with disodium ethylenedinitrilotetraacetate (EDTA) and its analytical application.

The pH-stat titration technique is an autonomous and very powerful tool for performing and monitoring chelatometric titrations of metal cations with great accuracy, poorly known, however, and seldom exploited. Based on measurement of the amount of strong base required to keep the pH of the test solution at a selected value during stepwise known additions of ethylenedinitrilotetraacetate (EDTA), it requires a glass electrode as the only sensor and is easily implemented on potentiometric titrators. It was introduced a quarter of century ago on an empirical basis for a very peculiar purpose (determination of calcium in diary products), but only very recently it was generalised and its fundamentals were thoroughly examined.

Effect of eluent composition and pH and chemiluminescent reagent pH on ion chromatographic selectivity and luminol-based chemiluminescence detection of Co(2+), Mn(2+) and Fe(2+) at trace levels.

The alkaline-luminol/H(2)O(2)-based chemiluminescent (CL) detection of Fe(2+), Co(2+), and Mn(2+), separated with a Dionex CS5A ion chromatographic phase was studied by means of a multi-pump flow system allowing the variation of the post-column solution composition. A perchlorate gradient at pH 1.9 (with HCl) was used to separate cations partially complexed with 5.

Headspace solid phase micro extraction GC-ECD determination of volatile organic chlorinated hydrocarbons in soils.

Soil samples were suspended in a suitable aqueous solvent and a solid phase microextraction (SPME) fibre was used to sample the headspace (HS) for five volatile chlorinated compounds (VOX). Their determination was made by GC-ECD technique in the splitless mode. Preliminary studies on the effects of methanol and of the sand/clay ratio on the fibre extraction were made.

Determination of biogenic amines in chocolate by ion chromatographic separation and pulsed integrated amperometric detection with implemented wave-form at Au disposable electrode.

A rapid and selective cation exchange chromatographic method coupled to integrated pulsed amperometric detection (PAD) has been developed to quantify biogenic amines in chocolate. The method is based on gradient elution of aqueous methanesulfonic acid with post column addition of strong base to obtain suitable conditions for amperometric detection. A potential waveform able to keep long time performance of the Au disposable electrode was set up.

Non-linear and non-constant variance calibration curves in analysis of volatile organic compounds for testing of water by the purge-and-trap method coupled with gas chromatography/mass spectrometry.

Currently used operating conditions for analysing volatile organic compounds (VOCs) by purge-and-trap gas chromatography/mass spectrometry (GC/MS) produced non-linear calibration curves with non-uniform variance. Second-order polynomial models therefore had to be used in weighted regression analysis of measurements of replicates spiked at various concentrations. A transparent procedure based on a reported method of very low computational complexity allowed calculation of the parameters of second-order models, confidence bands of regression lines, prediction bands, and confidence intervals of discriminated analyte concentrations.

Kinetic considerations on the electrogenerated luminescence of luminol at platinum electrode in the presence of hydrogen peroxide and oxygen.

The ECL behavior of the luminol/H2O2 and luminol/O2 systems was evaluated at Pt electrode by using different electroanalytical techniques such as chronoamperometry, cyclic and rotating disk electrode (RDE) voltammetry. Diffusive and kinetic parameters such as the diffusion coefficient of luminol, D, the number of exchanged electrons, n, and the apparent heterogeneous rate constant, kap, were determined in the maximum light emission conditions achieved at pH 11, at an electrode potential of 750 mV vs. SCE.