Search results for "liquid chromatography"
showing 10 items of 942 documents
Reduction of the enniatins A, A1, B, B1 by an in vitro degradation employing different strains of probiotic bacteria: Identification of degradation p…
2013
Abstract The degradation of the Fusarium mycotoxins ENs by 9 bacterial strains characteristic of the gastrointestinal tract like Bb. longum , Bb. bifidum , Bb. breve , Bb. adolescentes , Lb. rhamnosus , Lb. casei–casei , S. termofilus , Lb. ruminis , Lb. casei and twenty two strains of Saccharomyces cerevisiae was studied. The fermentations were carried out in the liquid medium of De Man Rogosa Sharpe (MRS) under anaerobic conditions for Bifidobacteria Streptococcus and Lactobacillus, and in Potato Dextrose Broth (PDB) for Saccharomyces strains, during 48 h. The degradation of the bioactive compounds ENs was also studied in a food system composed by wheat flour naturally contaminated by ENs…
Chromatography-mass spectrometry: Recent evolution and current trends in environmental science
2020
The coupling of chromatography to mass spectrometry has been a very important step in environmental science that has changed routine workflows opening a horizon of new and impressive possibilities. This hyphenated technique benefits from coupling as chromatography offers great separation power and comprises various techniques and mechanisms. In turn, chromatography exploits the identification capability of mass spectrometry and is able to provide nominal or exact mass charge ration (m/z) not only of the intact molecule but also of several characteristic fragments. The sensitivity, selectivity, specificity, and rapidity in chromatography–mass spectrometry make this technology highly powerful…
Hemocyanin subunit organization of the gastropod Rapana thomasiana
1999
Abstract RtH1 and RtH2, the two hemocyanin isoforms of the prosobranch gastropod Rapana thomasiana, have been purified by anion-exchange chromatography and studied by SDS–PAGE and immunoelectrophoresis. Both subunit types are built up of eight functional units (FUs). Under reducing conditions subunit RtH2 splits into two fragments, RtH2- a – f and RtH2- gh, suggesting the presence of a disulfide bridge between FU2- f and FU2- g. By proteolytic cleavage of the subunits into three-, two-, and single-FU fragments, purification of fragments by HPLC, N-terminal sequencing of the peptides, and crossed-line immunoelectrophoresis, FUs- a – h of RtH2 and FU- a, FU- d, FU- e, and FU- f of RtH1 were i…
Identification of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster.
1988
Summary Using reversed-phase high-performance liquid chromatography with electrochemical detection we have demonstrated the occurrence of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster . The former is the first time that has been detected in vivo . The identification has been based on the retention times, hydrodinamic voltagrams and the differential concentration in three strains of Drosophila melanogaster . Compared to the wild type, the Punch 2 mutant has diminished levels of both pteridines, whereas Henna-recessive 3 lacks completely tetrahydropterin and has increased levels of tetrahydrobiopterin, as expected according to their biochemical lesions.
Determination of pharmaceuticals in soils and sediments by pressurized liquid extraction and liquid chromatography tandem mass spectrometry
2010
13 páginas, 4 figuras, 6 tablas.
High-performance liquid chromatographic study of the regulation of phospholipid metabolism in cultured adrenocortical cells
1994
Abstract A rapid high-performance liquid chromatographic (HPLC) method for the separation of phospholipids was developed for minute samples of total lipids (ca. 200 μg). The method was applied to the study of the phospholipid metabolism in adrenocortical cell cultures. A complete separation of the different cellular phospholipid classes was achieved in 40 min. Good resolution of the phospholipid peaks was obtained, which allowed the collection of each individual class of phospholipids for further analysis of radioactivity and fatty acid composition by gas chromatography. When cells were incubated with [U-14C]glycerol or [U-14C]palmitate the bulk of the radioactivity was found in cellular ph…
Extraction of β-blockers from urine with a polymeric monolith modified with 1-allyl-3-methylimidazolium chloride in spin column format
2020
Abstract A glycidyl methacrylate-based monolith was modified with imidazolium-based ionic liquid (IL) to be used as stationary phase for solid-phase extraction (SPE). The host monolithic support was prepared by in-situ UV polymerization in spin column format. Two approaches were developed to incorporate the IL into the polymeric monolithic matrix: generation of IL onto the surface monolith, and copolymerization by addition of the IL to the polymerization mixture, which gave the best results. The resulting sorbent materials were morphologically characterized and used for the isolation of five β-blockers from human urine samples. All SPE steps were accomplished by centrifugation, which reduce…
Evidence for Direct Binding of the First Component of Complement, C1, to Outer Membrane Proteins from Salmonella minnesota
1985
The outer membrane of gram-negative bacteria consists of a tight lattice of lipopolysaccharides (LPS), phospholipids, and proteins. It has been shown in E. coli and S. typhimurium that LPS molecules are exclusively localized in the outer layer of the outer membrane (Muhlradt and Golecki 1975; Smit et al. 1975; Funatura and Nikaido 1980). Localization of proteins in the outer membrane is also indicated by the fact that various major outer membrane proteins in association with LPS, serve as receptors for phages (Datta et al. 1977; Mu-TOH et al. 1978; Henning and Jann 1979; Yu and Mizushima 1982) and colicins (Kadner et al. 1979; Konisky 1979).
Analysis of pharmaceutical preparations containing antihistamine drugs by micellar liquid chromatography
2005
Rapid chromatographic procedures for analytical quality control of pharmaceutical preparations containing antihistamine drugs, alone or together with other kind of compounds are proposed. The method uses C18 stationary phases and micellar mobile phases of cetyltrimethylammonium bromide (CTAB) with either 1-propanol or 1-butanol as organic modifier. The proposed procedures allow the determination of the antihistamines: brompheniramine, chlorcyclizine, chlorpheniramine, diphenhydramine, doxylamine, flunarizine, hydroxyzine, promethazine, terfenadine, tripelennamine and triprolidine, in addition to caffeine, dextromethorphan, guaifenesin, paracetamol and pyridoxine in different pharmaceutical …
Computer Aided Evaluation of HPLC (High Pressure Liquid Chromatography) with Fluorometric Detection
1982
A program system for automated HPLC measurements of vitamin A concentration is reported. This system provides for guidance of operators, for control of apparatus and for supervision of quality measurements.