Search results for "Chromatography detector"
showing 10 items of 15 documents
In vitro antifungal activity of bioactive peptides produced by Lactobacillus plantarum against Aspergillus parasiticus and Penicillium expansum
2017
Abstract Food spoilage caused by mycotoxigenic moulds represents an important problem in food security. The antimicrobial peptides are compounds of natural origin constituted by a variable number (5–100) of amino acids held together through peptide bonds. In this work, the cell free supernatants (CFSs) containing peptides obtained from four strains of LAB were lyophilized, filtered and tested to determine the antifungal activity against Aspergillus Parasiticus and Penicillium expansum . CFS obtained by Lactobacillus plantarum showed the highest inhibition activity. CFS was fractionated by size exclusion chromatography and injected into the liquid chromatography coupled to diode array detect…
H-Point Curve Isolation Method for Coupled Liquid Chromatography and UV−Visible Spectrophotometry
2000
The H-point curve isolation method (HPCIM) for the detection of unknown interferences in chromatography is proposed. The method allows one to estimate the UV-vis spectra of interfering species in a sample as well as to test the purity of the chromatographic peaks. Besides the detection of the unknown interferences in a sample, this method allows one to calculate the concentration of an analyte in the presence of unknown compounds. To illustrate the reliability of the proposed method, samples of diuretics and amphetamines have been analyzed by normal- and reversed-phase high-performance chromatography.
Comparison of photodiode array, evaporative light scattering, and single-quadrupole mass spectrometric detection methods for the UPLC analysis of pyr…
2017
ABSTRACTIt is important to analyze pyrolysis liquids to evaluate the yield of valuable products as well as unfavorable by-products. This work focuses on choosing detectors for reversed-phase ultra high-performance liquid chromatography analysis of pyrolysis liquids. The linearity, sensitivity, precision, and recovery of photodiode array (PDA) detector, single-quadrupole mass spectrometer (MS), and evaporative light scattering (ELS) detector were compared for the quantitative determination of several typical compounds found in pyrolysis liquids. PDA and MS detectors were found to be suitable for the quantification of furans and phenol derivatives (furfural, vanillin, syringol), but sugars an…
Chemical reduction of the mycotoxin beauvericin using allyl isothiocyanate.
2011
Abstract Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains and known to have various biological activities. This study investigated the reduction of BEA present in the concentration of 25 mg/kg on a solution model (phosphate buffer saline at pH 4 and 7) and in wheat flour using allyl isothiocyanate (AITC) as a reactant. The concentration of the mycotoxin studied was evaluated using liquid chromatography coupled to the diode array detector (LC-DAD), whereas adducts formed between the BEA and AITC were examined by liquid chromatography coupled to mass spectrometry-linear ion trap (LC-MS-LIT). In solution, BEA reduction ranged from 20% t…
High-performance liquid chromatography of lactose with evaporative light scattering detection, applied to determine fine particle dose of carrier in …
2005
A method for quantification of the fine particle dose of lactose is described, using a hydrophilic interaction chromatography (HILIC) method and evaporative light scattering detection. The HILIC method used an aminopropyl column and a mobile phase consisting of acetonitril/water (80/20, v/v) for isocratic elution. Sensitive chromatography was obtained using a low concentration of water in the extraction solvent. The detection limit (RSD10%) at an injection volume of 10 microL is 10 microg/mL. Linearity was obtained in the range of 10-80 microg/mL (R(2)0.99). A relative standard deviation (RSD) of 0.5% (N=6) demonstrated good precision of the optimized method.
A cost-effective method for estimating di(2-ethylhexyl)phthalate in coastal sediments.
2013
This study describes the development of a new method for the analysis of di(2-ethylhexyl)phthalate (DEHP) using 0.1-0.3 g of sediment sample, based on matrix solid phase dispersion (MSPD) using C18 as dispersant phase (0.4 g) and acetonitrile-water as eluting solvent (3.4 mL 1:3.25, v/v). No evaporation step is required. 3 mL of extracts were processed on-line by in-tube solid phase microextraction (IT-SPME) coupled to capillary liquid chromatography (CapLC) and diode array detector (DAD). A short analytical column Zorbax SB C18 (35×0.5 mm, 5 μm) provided suitable results. FTIR-ATR was employed for characterizing sediment samples and MSPD procedure. The total analysis time was less than 20 …
Rapid whole protein quantification of staphylococcal enterotoxin B by liquid chromatography
2012
Abstract Food poisoning caused by Staphylococcus aureus is one of the most important foodborne diseases in the world. The ability of these bacteria to produce one or more enterotoxins in milk and dairy products is linked to staphylococcal food poisoning. Enterotoxin B (SEB) is an exotoxin produced by S. aureus and is one of the compounds most frequently involved in staphylococcal food poisoning worldwide. In this work, 20 samples of milk collected from restaurants have been studied for the presence of S. aureus enterotoxigenic strains. All the isolates from milk samples have been analysed by liquid chromatography-coupled with diode array detector for the rapid identification and quantificat…
A chemical approach for the reduction of beauvericin in a solution model and in food systems.
2014
Abstract Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains with a strong antibacterial, antifungal, and insecticidal activities. This study evaluated the reduction of BEA added at 25 mg/kg in phosphate buffer saline (PBS) solutions at pH of 4, 7 and 10, or to different cereal products (kernels and flours) by the bioactive compounds phenyl isothiocyanate (PITC) and benzyl isothiocyanate (BITC). The concentration of the mycotoxin was evaluated using liquid chromatography coupled to the diode array detector (LC-DAD). In solution, BEA reduction ranged from 9% to 94% on a time-dependent fashion and lower pH levels resulted in higher BEA re…
Degradation of the minor Fusarium mycotoxin beauvericin by intracellular enzymes of Saccharomyces cerevisiae
2013
Abstract Beauvericin (BEA) is a cyclic depsipeptide with antibiotic and insecticidal effects. It was discovered for the first time from the fungus Beauveria bassiana , but more significantly, is produced by several Fusarium strains, and considered a contaminant of several cereals like corn, wheat and barley. This study investigated the degradation of BEA by intracellular raw enzymes of four strains of Saccharomyces cerevisiae , named LO9, YE5, A34, and A17. The BEA at 25 mg/kg in a model solution and in corn flour was co-incubated with the raw enzymes from the four yeast strains, respectively. The reduction of BEA was evaluated using liquid chromatography coupled to a diode array detector (…
How Chemical and Sensorial Markers Reflect Gentian Geographic Origin in Chardonnay Wine Macerated with Gentiana lutea Roots?
2020
A Burgundian Chardonnay wine was enriched with Gentiana lutea root powders originating from two French mountain sites (Massif Central and Jura) in order to prepare semi-dry gentian aromatized Chardonnay wine-based drinks. These novel alcoholic beverages were chemically and sensorially characterized for evaluating if the gentian geographic origin influenced bitter and elemental and volatile composition and sensory profiles in the final products. For that, the chemical fingerprint of gentian powders and wines were carried by headspace solid phase microextraction gas chromatography coupled to mass spectrometry (HS&ndash