Search results for "Electrospray Ionization"
showing 10 items of 275 documents
Analysis of meat samples for anabolic steroids residues by liquid chromatography/tandem mass spectrometry.
2007
A rapid, specific and highly sensitive multi-residue method for the determination of anabolic steroid residues in bovine, pork and poultry muscle tissues was developed. The sample preparation involves enzymatic digestion followed by extraction with methanol. The crude extract was cleaned up by solid-phase extraction (SPE) combining C18 and NH2 columns. The detection was carried out by a highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using both positive and negative ionization modes. Natural and synthetic steroids covering different polarities could be extracted, concentrated and purified using one single method. Mobile phase com…
Measurement of pollution levels of N-nitroso compounds of health concern in water using ultra-performance liquid chromatography–tandem mass spectrome…
2017
International audience; This paper reports the development of a highly sensitive analytical method combining solid-phase extraction (SPE) with ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS), for the monitoring of ultra-trace levels of N-nitrosamines in water samples. Under optimized analytical conditions, chromatographic separation was performed in 3 min, in isocratic mode, using an Acquity UHPLC C18 column and a mobile phase consisting of acetonitrile, water, and formic acid (60:40:0.1, v/v/v) at a flow rate of 0.4 mL min−1. Electrospray ionization tandem interface was employed prior to mass spectrometric detection. Good linearity (R2 ≥ 0.9…
[N⋅⋅⋅I+⋅⋅⋅N] Halogen-Bonded Dimeric Capsules from Tetrakis(3-pyridyl)ethylene Cavitands
2016
Two [N⋅⋅⋅I+⋅⋅⋅N] halogen-bonded dimeric capsules using tetrakis(3-pyridyl)ethylene cavitands with different lower rim alkyl chains are synthesized and analyzed in solution and the gas phase. These first examples of symmetrical dimeric capsules making use of the iodonium ion (I+) as the main connecting module are characterized by 1H NMR spectroscopy, diffusion ordered NMR spectroscopy (DOSY), electrospray ionization mass spectrometry (ESI-MS), and ion mobility-mass spectrometry (TW-IMS) experiments. The synthesis and effective halogen-bonded dimerization proceeds through analogous dimeric capsules with [N⋅⋅⋅Ag+⋅⋅⋅N] binding motifs as the intermediates as evidenced by the X-ray structures of …
Development of Antioxidant Protein Extracts from Gilthead Sea Bream (Sparus aurata) Side Streams Assisted by Pressurized Liquid Extraction (PLE)
2021
The pressurized liquid extraction (PLE) technique was used, for the first time, to obtain protein extracts with antioxidant activity from side streams (muscle, heads, viscera, skin, and tailfins) of gilthead sea bream (Sparus aurata) in order to give added value to these underutilized matrices. Extraction conditions previously optimized for sea bass (Dicentrarchus labrax) side streams were applied. Protein recovery percentages were 22% (muscle), 33% (heads), 78% (viscera), 24% (skin), and 26% (tailfins), which represented an increase of 1.2–4.5-fold compared to control samples (extraction by stirring). The SDS-PAGE profiles revealed that PLE-assisted extraction influenced protein molecular …
Biomonitoring of Enniatin B1 and Its Phase I Metabolites in Human Urine: First Large-Scale Study
2020
Enniatins (Enns) are mycotoxins produced by Fusarium spp. which are a fungus widely spread throughout cereals and cereal-based products. Among all the identified enniatins, Enn B1 stands as one of the most prevalent analogues in cereals in Europe. Hence, the aim of this study was to evaluate for the first time the presence of Enn B1 and its phase I metabolites in 300 human urine samples using an ultrahigh-performance liquid chromatography high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) methodology. Enn B1 was detected in 94.3% of samples ranging from 0.007 to 0.429 ng/mL (mean value: 0.065 ng/mL). In accordance with previous in vitro and in vivo analysis, hydroxylated metabolites …
Ciclohexadespipeptide beauvericin degradation by different strains of Saccharomyces cerevisiae
2013
Abstract The interaction between the mycotoxin beauvericin (BEA) and 9 yeast strains of Saccharomyces cerevisiae named LO9, YE-2, YE5, YE-6, YE-4, A34, A17, A42 and A08 was studied. The biological degradations were carried out under aerobic conditions in the liquid medium of Potato Dextrose Broth (PDB) at 25 °C for 48 h and in a food/feed system composed of corn flour at 37 °C for 3 days, respectively. BEA present in fermented medium and corn flour was determined using liquid chromatography coupled to the mass spectrometry detector in tandem (LC–MS/MS) and the BEA degradation products produced during the fermentations were determined using the technique of the liquid chromatography coupled …
Antibacterial activity of the enniatin B, produced by Fusarium tricinctum in liquid culture, and cytotoxic effects on Caco-2 cells.
2011
The enniatins (ENs) are bioactive compounds of hexadepsipeptidic structure produced by several strains of Fusarium sp. The EN B was purified from extracts of Fusarium tricinctum growth on liquid culture of potato dextrose broth (PDB), using a semipreparative liquid chromatography (LC) followed by an analytical LC. The purity and the structure of the isolated compound were confirmed by the determination of the extinction coefficient and with electrospray ionization-mass spectrometry (ESI-MS) study. The pure fraction of EN B was utilized to determine the antibiotic effects on several bacterial strains that are considered normally pathogens of the intestinal tract: Escherichia coli, Enterococc…
Isolation, purification and antibacterial effects of fusaproliferin produced by Fusariumsubglutinans in submerged culture.
2009
To evaluate the fusaproliferin (FUS) production, Fusariumsubglutinans ITEM 2404 was grown in a liquid medium of potato being this mycotoxin purified by high-performance liquid chromatography (HPLC) with a C18 semipreparative column using a mobile phase of acetonitrile/H(2)O using gradient conditions. The purity of the fusaproliferin was verified by analytical HPLC, ultraviolet absorbance measurements, LC/MS-MS, (1)H NMR spectroscopy. The isolated FUS was shown to be free of impurities and can be used as a standard for routine analysis. The pure fusaproliferin was utilized to study the biological activity on Escherichiacoli and Staphylococcusaureus. This study demostred that FUS not showed s…
Study of the chemical reduction of the fumonisins toxicity using allyl, benzyl and phenyl isothiocyanate in model solution and in food products
2012
Abstract Fumonisins (FBs) are bioactive compounds produced by several strains of Fusarium spp. which contain a polyketide structure similar to sphinganine. These mycotoxins contain a free amino group that could work as an electron donor and react with the electrophile carbon present within the isothiocyanate (ITC) group. The objective of this study was to determine the effect of ITCs (allyl, benzyl and phenyl) on the stability of FB 1 , FB 2 and FB 3 . Firstly, PBS solutions at three pH levels (4, 7 and 9) were prepared and added with pairs of one FB (1 mg/L) plus one ITC (1 mg/L). Then, gaseous ITC was used to fumigate corn kernels and corn flour contaminated with FBs produced by Gibberell…
1 H,13 C, 19 F NMR, and ESI mass spectral characterization of two geminal difluorosteroids
2008
Two geminal difluorosteroids, 3,3-difluoro-5β-cholan-24-oic acid (1) and 3,3-difluoro-5α-androstan-17-one (2), have been prepared from corresponding ketosteroids with diethylaminosulphurtrifluoride (DAST) treatment in moderate yields. The structures of 1 and 2 have been characterized by 1H, 13C, 19F NMR, and ESI mass spectral techniques. Copyright © 2008 John Wiley & Sons, Ltd.