1,721,001 research outputs found
NATO SPS ASI G5535 CETRARO 2019 “DETECTION, DIAGNOSIS, AND HEALTH CONCERNS OF TOXIC CHEMICAL BIOLOGICAL AGENTS"
No full textWater pollution is becoming dramatic because of increasingly invasive and deleterious anthropic activities.
A significant number of contaminants called "Emerging Pollutants” (EPs) resulting from point and diffuse pollution are present in the aquatic environment.
These compounds, belonging to pharmaceuticals, industrial chemicals, surfactants, personal care products, analgesics, antibiotics, hormones and a whole range of other pharmaceutical compounds including anti-inflammatory, anti- diabetic, and antiepileptic drugs, are not commonly monitored but have the potential to enter the environment and cause adverse ecological and human health effects (1).
The threat lies in the fact that the environmental and human toxinology of most of these compounds has not been well addressed yet and many of these compounds are not removed by the conventional WasteWater Treatment Plants (WWTPs). Moreover, when these contaminants pass through the drinking water treatment systems undergo trasformations that generate derivative substances whose chemical properties remain undetermined. For this reason, it is necessary to try to find low-cost and easy-to-handle alternative methods to solve this vast problem.
Fluoroquinolones, which are powerful antibiotics used in human and veterinary medicine for the treatment of diseases and infections are among the drugs most frequently found in environmental waters along with sulfonamides, tetracyclines and macrolides. The synergistic action of these drugs can cause what is known as "bacterial resistance", which is the cause of 700,000 annually people death in worldwide due to resistant infections according to Joint Research Center (JRC) 2018 report.. This means that if no action is taken the estimated annual deaths attributable to bacterial resistance will be 10 million by 2050.
Adsorption by using porous materials (like activated carbon, polymeric resins, natural clay and organoclay complex adsorbents) was found to be one of the most simple, efficient, cost-effective, flexible methods to remove fluoroquinolonesin the wastewater treatment process. However, this technique does not lead to the complete removal of parent chemicals and their degradation products and, consequently, other treatments are needed for their mineralization.
Advanced Oxidation Processes (AOPs) can be a good choice because, basically, involve the generation of highly reactive free radicals, which convert the organic contaminants into final non-toxic by-products.
Among the various semiconductors employed, TiO2 is the most preferable material for the photo-catalytic process (high photosensitivity, non-toxic nature, large band gap, chemical stability and low cost).
In this research the photocatalytic activity of this semiconductor immobilized onto the surface of glass borosilicate tubes was evaluated on levofloxacin (trade name Levaquin and other), which is an antibiotic used to treat a number of bacterial infections including acute bacterial sinusitis, pneumonia, urinary tract infections, chronic prostatitis, and some types of gastroenteritis. Kinetics of photoreactions were determined in ultrapure and ground water samples spiked with levofloxacin and photoproducts where identified by liquid chromatography coupled with micrOTOF-Q-II-Mass Spectrometer (LC-MS, Bruker Daltonik GmbH, Bremen)
Analysis of tomato glycoalkaloids by liquid chromatography coupled with electrospray ionization tandem mass spectrometry
No full textSteroidal glycoalkaloids (SGAs) extracted from tomato leaves and berries (Lycopersicon esculentum Mill.) were separated and identified using optimized reversed-phase liquid chromatography with electrospray ionization (ESI) and ion trap mass spectrometry (ITMS). The ESI source polarity and chromatographic conditions were evaluated. The ESI spectra contain valuable information, which includes the mass of SGAs, the mass of the aglycones, and several characteristic fragment ions. Cleavage at the interglycosidic bonds proximal to the aglycones is the most prominent process in the ESI process. A protonated molecule, [M+H](+), accompanied by a mixed adduct ion, [M+H+Na](2+), was observed for a-tomatine (i.e., m/z 1034.7 and 528.9) and dehydrotomatine (i.e., m/z 1032.6 and 527.9) in positive ion mode spectra. The structures of these tomato glycoalkaloids were confirmed using tandem mass spectrometry. The identification of a new alpha-tomatine isomer glycoalkaloid, named filotomatine (MW 1033), which shares a common tetrasaccharide structure (i.e., lycotretraose) with alpha-tomatine and dehydrotomatine, and soladulcidine as an aglycone, is described for the first time. It occurs in significant amounts in the extracts of wild tomato foliage. Multistage mass spectrometry both of the protonated molecules and of the doubly charged ions was used for detailed structural elucidation of SGAs. Key fragmentations and regularities in fragmentation pathways are described and the fragmentation mechanisms involved are proposed
FLUOROQUINOLONES IN WATER: REMOVAL ATTEMPS BY INNOVATIVE AOPS
Full text linkThe photocatalytic activity of TiO2 semiconductor immobilized onto the surface of glass borosilicate tubes was evaluated for measuring levofloxacin, which is an antibiotic used to treat a number of bacterial infection
Establishing the occurrence of major and minor glucosinolates in Brassicaceae by LC-ESI-hybrid linear ion-trap and Fourier-transform ion cyclotron resonance mass spectrometry
No full textGGlucosinolates (GLSs) are sulfur-rich plant secondary metabolites which occur in a variety of cruciferous vegetables and among various classes of them, genus Brassica exhibits a rich family of these phytochemicals at high, medium and low abundances. Liquid chromatography (LC) with electrospray ionization in negative ion mode (ESI-) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS) was employed for the selective and sensitive determination of intact GLSs in crude sample extracts of broccoli (Brassica oleracea L. Var. italica), cauliflower (B. oleracea L. Var. Botrytis) and rocket salad (Eruca sativa L.) with a wide range of contents. When LTQ and FTICR mass analyzers are compared, the magnitude of the limit of detection was ca. 5/6-fold lower with the FTICR MS. In addition, the separation and detection by LC–ESI-FTICR MS provides a highly selective assay platform for unambiguous identification of GLSs, which can be extended to lower abundance (minor) GLSs without significant interferences of other compounds in the sample extracts. The analysis of Brassicaceae species emphasized the presence of eight minor GLSs, viz. 1-methylpropylGLS, 2-methylpropyl-GLS, 2-methylbutyl-GLS, 3-methylbutyl-GLS, n-pentyl-GLS, 3-methylpentyl-GLS, 4-methylpentyl-GLS and n-hexyl-GLS. The occurrence of these GLSs belonging to the saturated aliphatic side chain families C
4
,C
5
and C
, presumably formed by chain elongation of leucine, homoleucine and dihomoleucine as primary amino acid precursors, is described. Based on their retention behavior and tandem MS spectra, all these minor compounds occurring in plant extracts of B. oleracea L. Var. italica, B. oleracea L. Var. Botrytis and E. sativa L. were tentatively identified
IDENTIFICAZIONE DI COMPOSTI ACIDI NSO IN GREGGIO DI PETROLIO ATTRAVERSO SPETTROMETRIA DI MASSA A RISONANZA CICLOTRONICA IN TRASFORMATA DI FOURIER
No full textRecenti lavori hanno mostrato l’utilità della spettrometria di massa a risonanza ciclotronica abbinata alla ionizzazione electrospray (ESI/FT-ICR-MS) nella determinazione dei composti polari dei distillati del petrolio. L’eccellente accuratezza di massa e la grande capacità risolutiva rendono questa tecnica di elezione per l’identificazione di tali composti nel greggio di petrolio, anche in assenza di una preventiva separazione cromatografica.
Nel presente lavoro vengono presentati i primi risultati di uno studio condotto mediante ESI/FT-ICR-MS su campioni di greggio di petrolio prelevati a Viaggiano (PZ). Le elevate potenzialità della tecnica utilizzata hanno consentito di separare più di 3000 ioni in una singola analisi di massa, permettendo in tal modo la determinazione non ambigua della loro composizione elementare, della classe a cui essi appartengono (numero di eteroatomi N, O, S) e della loro tipologia (numero di anelli o doppi legami)
Analysis of tomato glycoalkaloids by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.
Full text linkSteroidal glycoalkaloids (SGAs) extracted from tomato leaves and berries (Lycopersicon esculentum Mill.) were separated and identified using optimized reversed-phase liquid chromatography with electrospray ionization (ESI) and ion trap mass spectrometry (ITMS). The ESI source polarity and chromatographic conditions were evaluated. The ESI spectra contain valuable information, which
includes the mass of SGAs, the mass of the aglycones, and several characteristic fragment ions. Cleavage at the interglycosidic bonds proximal to the aglycones is the most prominent process
in the ESI process. A protonated molecule, [M+H]+, accompanied by a mixed adduct ion, [M+H+Na]2+, was observed for a-tomatine (i.e., m/z 1034.7 and 528.9) and dehydrotomatine (i.e., m/z 1032.6 and 527.9) in positive ion mode spectra. The structures of these tomato glycoalkaloids were confirmed using tandem mass spectrometry. The identification of a new a-tomatine isomer
glycoalkaloid, named filotomatine (MW 1033), which shares a common tetrasaccharide structure (i.e., lycotretraose) with a-tomatine and dehydrotomatine, and soladulcidine as an aglycone, is described for the first time. It occurs in significant amounts in the extracts of wild tomato foliage. Multistage mass spectrometry both of the protonated molecules and of the doubly charged ions was used for detailed structural elucidation of SGAs. Key fragmentations and regularities in fragmentation pathways are described and the fragmentation mechanisms involved are propose
Naturally Occurring Glucosinolates in Plant Extracts of Rocket Salad (Eruca sativa L.) Identified by Liquid Chromatography Coupled with Negative Ion Electrospray Ionization and Quadrupole Ion-Trap Mass Spectrometry
No full textA method for the comprehensive profiling of intact glucosinolates (GLSs), major and minor, occurring in leaves and seeds of rocket salad (Eruca sativa L.) is presented using optimized reversed-phase liquid chromatography (RP-LC) with electrospray ionization (ESI) ion trap mass spectrometry (ITMS). ESI-ITMS in the negative mode was confirmed to be very suitable to analyze these compounds in crude extracts. After extraction from the plant material with methanol/water (70:30 v/v) at 70 degrees C, the analytes of interest were separated on a C18 column using an eluent acidified with formic acid (0.1%) and modified with acetonitrile. All the GLSs found in leaves of rocket salad gave good signals corresponding to the deprotonated precursor ion, [M-H](-). Although the mass spectra also exhibited an analytically important non-covalent adduct ion at [2M-H](-), the structures of glucosinolates were confirmed by extensive sequential MS analysis, thereby substantially improving the identification of unknown compounds. The results obtained not only revealed in leaves of E. sativa at least twelve species of GLSs including seven aliphatic compounds (glucoraphanin with [M-H](-) at m/z ratio of 436, glucoerucin at m/z 420, 4-mercaptobutyl-GLS at m/z 406, progoitrin/epiprogoitrin at m/z 388, sinigrin at m/z 358,4-methylpentyl- and n-hexyl-GLS at m/z 402) and three indole glucosinolates (i.e., three N-heterocyclic compounds: 4-hydroxyglucobrassicin and 5-hydroxyglucobrassicin at m/z 463, and 4-methoxy-glucobrassicin at m/z 477), but also two structurally related compounds containing one intermolecular disulfide linkage (4-(beta-D-glucopyranosyldisulfanyl)butyl-GLS at m/z 600 and a dimeric 4-mercaptobutyl-GLS at m/z 811). This latter symmetric disulfide was previously considered as an artefact formed during extraction of GLSs from vegetative tissues. Glucosinolates were detected in the leaves with a wide range of contents (10-200 mu mol/g) and a great variation in the composition. Only three GLSs were identified in seeds of rocket salad, namely glucoraphanin, glucoerucin and 4-methoxyglucobrassicin. As expected, the most abundant GLS in seeds is glucoerucin. The feasibility of the strategy was also demonstrated using a rapeseed extract of certified reference material (BCR367R). The results indicated the usefulness of this method for a rapid, sensitive and comprehensive profiling of the GLS family naturally occurring in extracts of crude plant matter
Applications of LC-MS for Detection of some Chemicals and their Metabolites in Water
Full text linkSurface waters are at risk from certain specific chemicals (priority substances) that could cause harm to the aquatic ecosystem (fish, plants, food chain, etc.) or affect human health through exposure to water (e.g. drinking, bathing, seafood, etc.). The Water Framework Directive (WFD) [1] requires the Commission to come forward with a strategy on pollution of surface waters. The European Directive 2000/60/CE stresses the need of adopting measures against water pollution in order to achieve a progressive reduction of contaminants and recuperate water for new uses.
The main objective is the application of LC-MS for the identification of polluting chemical compounds and their degradation intermediates in water. In this poster some results are reported about the identification of:
- tetra-hydro-cannabinol (THC) and other metabolites of Cannabis found in real water samples collected from the effluent of a wastewater treatment plant (WWTP) in Vila Nova De Gaia (Portugal),
- levofloxacin and MCPA and their metabolites in water samples undergone heterogeneous photocatalytic degradation using titanium dioxide coatings (TIO2).
Results of this investigation show as the mass spectrometry is very important for the detection of different polluting chemicals at low concentration. Our and literature findings demonstrate that
- traditional water treatments are not able to remove contaminants from wastewater and consequently recalcitrant pollutant water can entry the water cycle;
- the heterogeneous photo-catalytic system tested in our experiments is able to degrade the chemicals used as model molecules and may find application in the remediation of water contaminated with recalcitrant residues due to poor efficiency of treatment plants normally adopted for the purification of wastewater.
To obtain accurate masses and molecular formulae,
to identify unknown or unexpected and unusual metabolites,
to suggest degradation pathways
the structural identification of parent molecules and derivatives in very low concentrations represents a great benefit for environmental analytical purpose
Collision-Induced Dissociation of the A+2 Isotope Ion Facilitates Glucosinolates Structure Elucidation by ESI-Tandem Mass Spectrometry with a Linear Quadrupole Ion Trap
No full textAn approach is presented that can be of general applicability for structural elucidation of naturally occurring glucosinolates (GLSs) in crude plant extracts based on the fragmentation of isotopic A and A + 2 peaks. The most important fragmentation pathways were studied by tandem mass spectrometry (MS(n), n = 2, 3) using a linear quadrupole ion trap (LTQ) upon GLSs separation by optimized reversed-phase liquid chromatography (RPLC) and electrospray ionization (ESI) in negative ion mode. As the LTQ MS analyzer ensures high sensitivity and linearity, the fragmentation behavior under collision induced dissociation (CID) of the isotopic peaks A and A + 2 as precursor ions was carefully examined. All GLSs (R-C(7)H(11)O(9)NS(2)(-)) share a common structure with at least two sulfur atoms and significant isotopic abundance of (34)S. Thus, dissociation of the +2 Da isotopomeric ions results in several fragment ion doublets containing a combination of (32)S and (34)S. Accordingly, their relative abundances allow one to speed up the structural recognition of GLSs with great confidence, as it produces more structurally informative ions than conventional tandem MS performed on A ions. This approach has been validated on known GLSs bearing two, three, four, and six sulfur atoms by comparing expected and measured isotopic peak abundance ratios (I(A)/I(A+2)). Both group- and compound-specific fragments were observed; the predominant pathway of fragmentation of GLSs gives rise to species having the following m/z values, [M - SO(3) - H](-), [M - 196 - H](-), [M - 178 H](-), and [M - 162 - H](-) after H rearrangement from the R side chain. The present strategy was successfully applied to extracts of rocket salad leaves (Eruca sativa L.), which was sufficient for the chemical identification of a not already known 6-methylsulfonyl-3-oxohexyl-GLS, a long-chain-length aliphatic glucosinolate, which contains three sulfurs and exhibits a deprotonated molecular ion at m/z 494.1
Simulated ageing of crude oil and advanced oxidation processes for water remediation since crude oil pollution
Full text linkCrude oil can undergo biotic and abiotic transformation processes in the environment. This article deals with the fate of an Italian crude oil under simulated solar irradiation to understand (i) the modification induced on its composition by artificial aging and (ii) the transformations arising from different advanced oxidation processes (AOPs) applied as oil-polluted water remediation methods. The AOPs adopted were photocatalysis, sonolysis, and, simultaneously, photocatalysis and sonolysis (sonophotocatalysis). Crude oil and its water-soluble fractions underwent analysis using GC-MS, liquid-state1H-NMR, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and fluorescence. The crude oil after light irradiation showed (i) significant modifications induced by the artificial aging on its composition and (ii) the formation of potentially toxic substances. The treatment produced oil oxidation with a particular effect of double bonds oxygenation. Non-polar compounds present in the water-soluble oil fraction showed a strong presence of branched alkanes and a good amount of linear and aromatic alkanes. All remediation methods utilized generated an increase of C5 class and a decrease of C6-C9 types of compounds. The analysis of polar molecules elucidated that oxygenated compounds underwent a slight reduction after photocatalysis and a sharp decline after sonophotocatalytic degradation. Significant modifications did not occur by sonolysis
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