Biological Activities and ADMET-Related Properties of Novel Set of Cinnamanilides.

A series of nineteen novel ring-substituted -arylcinnamanilides was synthesized and characterized. All investigated compounds were tested against as the reference strain, two clinical isolates of methicillin-resistant (MRSA), and . (2)--[3-Fluoro-4-(trifluoromethyl)phenyl]-3-phenylprop-2-enamide showed even better activity (minimum inhibitory concentration (MIC) 25.

Characterization of Klason lignin samples isolated from beech and aspen using microbore column size-exclusion chromatography.

The present study is focused on the separation and characterization of lignin samples isolated by Klason method from European beech (Fagus sylvatica) broadleaf hardwood and European aspen (Populus tremula) broadleaf softwood by size-exclusion chromatography. The separation was carried out using dimethylformamide as major component of the mobile phase and a 3 mm id microbore column packed with hydroxyethyl methacrylate gel, calibrated with polystyrene standards. The influence of mobile phase composition and sample solvent composition on the chromatographic behavior and molar mass distributions was investigated.

Development of a precolumn derivatization HPLC method with diode-array detection for the determination of amino sugars in peat and soil humic acids.

The work is focused on the development of a high-performance liquid chromatography method with diode-array detection for the separation and quantitation of the three most abundant amino sugars; d-glucosamine, d-galactosamine, and d-mannosamine. The high-performance liquid chromatography separation was carried out by reversed-phase chromatography on Chromolith Performance RP-18e monolithic column after acid hydrolysis (5 M HCl) and precolumn derivatization of samples using diethyl ethoxymethylenemalonate. Gradient elution and a mobile phase composed of ammonium formate buffer solution (10 mmol/L, pH 3.

Fast ultra-high-performance liquid chromatography with diode array and mass spectrometry method for determination of tadalafil drug substance and its impurities.

Tadalafil is used for the treatment of erectile dysfunction. Its related patents expired in 2016, and so related generic drug production is predicted to be increased. This work is focused on developing a fast ultra-high-performance liquid chromatography with diode array detection and/or mass spectrometry detection for the separation and determination of tadalafil and its impurities in pharmaceutical samples.

Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.

Characterization and analysis of soil humic acids by off-line combination of wide-pore octadecylsilica column reverse phase high performance liquid chromatography with narrow bore column size-exclusion chromatography and fluorescence detection.

Liquid chromatography method arranged around RP-HPLC using step-wise gradients of dimethylformamide (DMF) in pH 3.0 aqueous phosphate buffered mobile phase and a wide-pore (30 nm) 4mm inner diameter (I.D.

Some theoretical and practical aspects in the separation of humic substances by combined liquid chromatography methods.

Permanent need to understand nature, structure and properties of humic substances influences also separation methods that are in a wide scope used for fractionation, characterization and analysis of humic substances (HS). At the first glance techniques based on size-exclusion phenomena are the most useful and utilized for relating elution data to the molecular mass distribution of HS, however, with some limitations and exceptions, respectively, in the structural investigation of HS. The second most abundant separation mechanism is reversed-phase based on weak hydrophobic interactions beneficially combined with the step gradients inducing distinct features in rather featureless analytical signal of HS.

On-line flow-through extraction-preconcentration-large volume injection-RP LC for trace determination of pyrethroids in Slovak soil.

A rapid micro-analytical multiresidue method was developed for analysis of pyrethroids (kadethrin K, cypermethrin C and permethrin P) in soil micro-sample (200 mg). It uses on-line flow-through extraction of soil micro-samples (packed into a short glass column) with a methanol-aqueous citric acid buffer mixture, successive on-line SPE preconcentration of analytes from the extract and on-line RP-HPLC analysis with UV photometric detection. The separation of pyrethroids is performed on a Purospher RP-18e column with methanol/water as mobile phase.

Reversed phase liquid chromatography trace analysis of pesticides in soil by on-column sample pumping large volume injection and UV detection.

The idea of utilization of one hydraulic line of a common commercial HPLC pump for direct on-column sample pumping injection of large sample volumes, 20 mL, was further investigated with the aim to develop multicomponent pesticides trace residues HPLC method in gram soil samples. Target pesticides group involve asulam, atrazine, 2,4-D, PCA, propazine, simazine, 4-chloro-2-methylphenoxyacetic acid, 2-(4-chloro-2-tolyloxy) propionic acid, chlortoluron, metoxuron, epoxiconazole. The results proved the applicability of this approach in experiments with mixtures of analytes at low ng/mL levels.

Method of fast trace microanalysis of the chiral pesticides epoxiconazole and novaluron in soil samples using off-line flow-through extraction and on-column direct large volume injection in reversed-phase high performance liquid chromatography.

An analytical method combining off-line flow-through extraction of a soil micro-sample (mass around 100 mg, packed into a short HPLC glass column) and direct on-column large-volume injection (LVI up to 1.00 mL) of a methanol-water soil extract onto a conventional C18 RP HPLC column enabled fast (within 3.5 minutes) trace micro-analysis of the relatively new chiral pesticides epoxiconazole (E) and novaluron (N), respectively.

Method of analysis of a selected group of pyrethroids in soil samples using off-line flow-through extraction and on-column direct large-volume injection in reversed phase high performance liquid chromatography.

An analytical method using flow-through extraction of a soil sample filled in a short HPLC column with methanol or methanol-water mixtures and large-volume injection in RP-HPLC has been developed for the simultaneous determination of residues of three pyrethroids--kadethrin, cypermethrin, and permethrin--from soil samples. The developed RP-HPLC method enables separation of four diastereoisomers of cypermethrin into three peaks and resolution of two diastereoisomers of permethrin. The UV photometric detection limits of direct on-column large-volume injection of 1.

New approach to large-volume injection in reversed-phase high performance liquid chromatography: determination of atrazine and hydroxyatrazine in soil samples.

A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.

Reversed-phase liquid chromatographic characterization and analysis of air particulates humic (-like) substances in presence of pollens.

Newly developed method for characterisation and analysis of humic substances (HS) and humic-like substances (HULIS) in air dust particles was tested for potential interferences caused by abundant co-sampled pollens (common dandelion, common wormwood-absinth, apple tree). RP-HPLC using 10-step gradient of dimethylformamide (DMF) in a buffered aqueous mobile phase and a wide-pore (30 nm) octadecylsilica column has been applied to the analysis of HS and HULIS using tandem of spectrophotometric (DAD) and fluorimetric detection (FLD). Achieved results suggest that the devised method is reliable for characterisation, fractionation and analysis of terrestrial HS, air dust HS and air particulate HULIS in liquid extracts at a trace concentration levels.

Rapid analysis of porphyrins at low ng/l and microg/l levels in human urine by a gradient liquid chromatography method using octadecylsilica monolithic columns.

Rapid gradient RP-HPLC method with fluorimetric detection for trace analysis of diagnostically significant porphyrins in human urine was developed for clinical and diagnostic purposes. Results show that optimized high-pressure gradient elution and monolithic column Chromolith SpeedRod RP18e enabled separation of seven urine porphyrins including baseline separation of I and III positional isomers of uro- and coproporphyrins within 3.2 min.

Role of biological matrices during the analysis of chiral drugs by liquid chromatography.

The review article covers advances of chiral drugs analysis by high-performance liquid chromatography (HPLC) methods achieved during last 10 years. Emphasis is given to various aspects of influence of biological matrix in pharmacodynamics, pharmacokinetics, HPLC analysis. Discussed is composition of main biological matrices from the point of view of potential interferences to above-mentioned fields of study.

Novel stepwise gradient reversed-phase liquid chromatography separations of humic substances, air particulate humic-like substances and lignins.

RP-HPLC using stepwise gradients of dimethylformamide (DMF) in buffered aqueous mobile phase and a wide-pore (30 nm) octadecylsilica column has been applied to the analysis of soil, peat and air particulate humic and humic-like substances (HSs), as well as lignin, in order to demonstrate the usefulness of the approach for their characterization even at trace concentration level. Tandem combination of spectrophotometric (DAD) and fluorimetric detection was used to get more detailed information on chromatographic behaviour of HSs. The results showed that ten-step gradient can induce distinct features of HSs and lignins.