Ultra-high performance liquid chromatography–
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A fingerprinting method for chemical screening of microbial metabolites, potential antibiotics, in spent cultivation broths is described. The method is based on high-throughput ultra-high-performance liquid chromatography (UHPLC) separation with UV detection (photodiode array detector). Thirteen antibiotic standards and four cultivation broths were used for the method development. The comparison of ten liquid-liquid and solid phase extraction protocols for sample clean-up and pre-concentration revealed that Oasis HLB C18 sorbent gives the best recoveries. The Acquity BEH C18 chromatographic column was chosen for the samples separation with respect to its universality, selectivity, efficiency and robustness. The method is presented by two 3D fingerprints for every sample that was obtained under different, acidic and alkaline, UHPLC conditions. The acidic mobile phase consisted of 0.5% phosphoric acid with methanol and the alkaline mobile phase of 1mM ammonium formate, pH 9 with acetonitrile. Each pair of 3D fingerprints includes the following physico-chemical information: polarity (retention time), presence and characterization of chromophores (UV spectra), compound concentration (detector response), and acid-base properties (influence of different pH of the aqueous parts of mobile phases on retention times). The sample extraction and method validation were assessed with relative standard deviation (RSD) of 0.5, 5.0 and 20.0% for retention times, peak areas and minor compound peak areas, respectively.
- MeSH
- Actinobacteria chemie metabolismus MeSH
- antibakteriální látky analýza metabolismus MeSH
- extrakce na pevné fázi MeSH
- fermentace MeSH
- kultivační média chemie metabolismus MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
In theory, with identical stationary phase chemistry, the transfer of an HPLC method to UHPLC conditions is straightforward and necessitates the calculation of new conditions based on column and instrument geometries. Occasionally, undesirable changes in selectivity, retention or efficiency have been reported and have been attributed to a frictional heating phenomenon that is due to the elevated generated pressure drop. In the present study, the frictional heating in a UHPLC system was evaluated experimentally under gradient elution conditions (acetonitrile/buffer at pH 3 and 9) with generated pressure drops in the range of 100-1000 bar on both 1.0mm and 2.1mm I.D. columns using a mixture of 10 representative basic, acidic and neutral pharmaceutical compounds. Under adiabatic conditions (i.e., still-air oven), the longitudinal temperature gradient was estimated at +4 °C, +8 °C and +16 °C at 300, 600 and 1000 bar, respectively, on a 2.1mm I.D. column using an empirical measurement procedure. With the 1.0mm I.D. column, these values were reduced to +3 °C, +6 °C and +12 °C, respectively. Finally, various approaches to eliminate or at least to reduce the effect of frictional heating are briefly discussed.
A new separation and quantification method using ultra-performance liquid chromatography (UPLC) with UV detection was developed for detection of lincomycin traces in fermentation broth of different Streptomyces spp. A similar high-performance liquid chromatography (HPLC) protocol was simultaneously developed for comparison purposes. Both methods were validated and showed a linear range of detector response for quantification of lincomycin in concentration from 3.125 to 1000.0 microgml(-1) with correlation coefficient 0.999 and recoveries ranging from 81.5 to 89.85% with precision < or =5%. Compared with the HPLC, the UPLC method offered high sample throughput and about 10 times lower consumption of solvents. The developed assays were used for determination of lincomycin production in genetically manipulated production strain Streptomyces lincolnensis and for determination of lincomycin production after heterologous expression of lincomycin biosynthetic gene cluster in non-producing strain Streptomyces coelicolor.
- MeSH
- chromatografie kapalinová metody MeSH
- fermentace MeSH
- financování organizované MeSH
- geneticky modifikované organismy metabolismus MeSH
- linkomycin analýza MeSH
- senzitivita a specificita MeSH
- spektrofotometrie ultrafialová metody MeSH
- Streptomyces genetika metabolismus MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
Candida albicans is generally one of the most commonly isolated fungal pathogen from human body. It is a frequent cause of nosocomial infections, bloodstream infections, urinary infections and mucosal infections of oral cavity and vagina C. albicans can grow as hyphae, pseudohyphae, or budding yeast. Morphological conversion of a yeast form to pseudohyphal or hyphal one is often characterized by the change of commensal status to an invasive form. Farnesol and tyrosol can participate in these transformation processes as quorum sensing molecules together with some physical-chemical factors. A new analytical method for identification and quantification of biologically active substances farnesol and tyrosol using ultra high performance liquid chromatography (UHPLC) in connection with tandem mass spectrometry was developed. The analytes were separated on Acquity BEH C18 analytical column using binary mobile phase consisting of acetonitrile and formic acid 0.075% (75:25) at flow-rate 0.20 ml/min. SRM (selected reaction monitoring) mode was applied in order to ensure sufficient selectivity and sensitivity using the first most intensive transition as a quantitative (121>77 and 205>121) and second one for the confirmation purposes (121>93 and 205>109). The method was validated in terms of linearity (>0.9994), precision (0.5-3.8% RSD), accuracy (78.9-106.0%), LOD (limit of detection) and LOQ (limit of quantitation). The method can serve as an analytical tool for the detection and determination of quorum-sensing molecules in biological samples.
- MeSH
- Candida albicans chemie MeSH
- farnesol analýza chemie MeSH
- fenethylalkohol analogy a deriváty analýza chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- kalibrace MeSH
- lidé MeSH
- limita detekce MeSH
- quorum sensing MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
1st ed. 564 s. : il.
Hops represent an important natural source of bioactive polyphenols, particularly proanthocyanidins, which can contribute to prevention of several civilization diseases, owing to their antioxidant and radical scavenging activity. We have developed a high-throughput ultra-high-performance liquid chromatography time-of-flight mass spectrometry profiling method, which can be used for monitoring of bioactive proanthocyanidins in hops. The method was applied for analysis of hops of four Czech varieties (Saaz, Sladek, Preminat and Agnus) from the 2011 crop (9 localities, 11 samples) and the 2012 crop (24 localities, 40 samples). Hop samples were extracted by acetone and the analytes were separated on the Acquity UPLC BEH Shield RP18 column. Partial validation of the method revealed a satisfactory intra-day repeatability of the method for retention times (relative standard deviation within 1.39%) as well as areas under the peaks (within 9.89%). Experimental data were evaluated using principal component analysis and cluster analysis. Significant amounts of di-, tri- and tetramer proanthocyanidins consisting of (epi)catechin and (epi)gallocatechin were found in the hop samples. The dependence of the proantocyanidin composition on both the variety and the growing locality was observed. Specifically, the traditional Saaz variety contained more frequently oligomers formed by (epi)catechin units only, whereas the varieties Premiant and Agnus produced oligomers consisting of (epi)catechin as well as (epi)gallocatechin units. The relative abundance of proanthocyanidins in studied hop varieties from the two crops, 2011 and 2012, did correspond to each other. In the further perspective, the method may also be used for prediction of qualitative marks or authenticity verification of hops.
- MeSH
- aceton chemie MeSH
- analýza hlavních komponent MeSH
- Humulus chemie MeSH
- katechin analogy a deriváty izolace a purifikace MeSH
- proantokyanidiny analýza chemie MeSH
- reprodukovatelnost výsledků MeSH
- rozpouštědla chemie MeSH
- rychlé screeningové testy MeSH
- shluková analýza MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Simvastatin and atorvastatin belong to the group of hypolipidemic drugs, more exactly to the second generation of inhibitors of microsomal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. They induce a significant reduction in total cholesterol, low-density lipoprotein cholesterol and plasma triglycerides, therefore they are widely used in the treatment of hypercholesterolemia even of its severe form-familiar hypercholesterolemia. Simvastatin and atorvastatin as the most widely used statins in clinical treatment and their hydroxy-acid/lactone forms were determined by means of UPLC in connection with triple quadrupole mass spectrometer. Deuterium labeled reference standard compounds were used as internal standards for the quantitation. Separation was performed on Acquity BEH C18 (100 mm x 2.1 mm, 1.7 microm) using gradient elution by mobile phase containing acetonitrile and ammonium acetate pH 4.0, which is convenient in order to prevent interconversion of analytes. ESI in positive mode was used for the ionization of all compounds. Two SRM (selected reaction monitoring) transitions were carefully optimized for each analyte in order to get high sensitivity and selectivity. SPE on Discovery DSC-18 was used as a sample preparation step. Intra-day precision was generally within 10% RSD, while inter-day precision within 15% RSD. Method accuracy expressed as recovery ranged from 75 to 100%. The method was validated with the sensitivity reaching LOQ 0.08-5.46 nmol/l and LOD 0.01-1.80 nmol/l in biological samples. Atorvastatin, simvastatin, its metabolites and hydroxy-acid/lactone forms were monitored in human serum and in lipoprotein fractions (LDL, HDL and VLDL) at patients with end stage renal diseases.
- MeSH
- anticholesteremika krev terapeutické užití MeSH
- hypercholesterolemie farmakoterapie MeSH
- kyseliny heptylové krev terapeutické užití MeSH
- lidé středního věku MeSH
- lidé MeSH
- pyrroly krev terapeutické užití MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- senzitivita a specificita MeSH
- simvastatin krev terapeutické užití MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- Publikační typ
- hodnotící studie MeSH
- práce podpořená grantem MeSH
