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Biomedical subjects

Bogusław Buszewski

Publications and source records attributed to Bogusław Buszewski.

At least 19 recordsLinked to original sources
PubMed2006

HPLC columns partition by chemometric methods based on peptides retention.

In recent years, multivariate techniques have been utilized to evaluate reversed-phase high-performance liquid chromatographic data. In the present study, 11 high-performance liquid chromatography (HPLC) columns were divided into several groups according to the retention factors of 12 peptides. Principal component analysis (PCA) and cluster analysis (CA) were used in column and peptides' comparison and grouping. CA results indicated that all stationary phases may be generally grouped into several clusters, due to stationary phase structure and properties. On the other hand, interesting results were obtained with the use of PC. There is almost linear relationship between classified HPLC columns in the space of new PCs, which is connected with meaning of the PC's reflected in their loading values. The first component describes non-polar properties of peptides, whereas the second component is loaded with polar peptides having much lower logP values. PCA and CA were also used in peptides comparison however, complete explanation of peptides grouping still remains unclear.

Chromatography, High Pressure Liquid↗
PubMed2006

Considerations on influence of charge distribution on determination of biomolecules and microorganisms and tailoring the monolithic (continuous bed) materials for bioseparations.

The importance of continuous beds (monoliths) as separation materials is connected with their better chromatographic properties and easier preparation in comparison to particulate-packed columns. Moreover the tuning of porosity as well as surface chemistry can lead to obtaining of highly selective materials, especially useful in separation of biologically important compounds or even microorganisms. To obtain high selectivity for such analytes as e.g. proteins, it is often important to have a knowledge about their shape, size, charge and finally charge distribution. This article presents our considerations on the charge distribution on the monolithic stationary phase and surface of such species as proteins or microorganisms as well as its eventual influence on the separation or sample preparation processes and tuning of their selectivity.

Animals↗
PubMed2006

Study of the selection mechanism of heavy metal (Pb2+, Cu2+, Ni2+, and Cd2+) adsorption on clinoptilolite.

The study was carried out on the sorption of heavy metals (Ni2+, Cu2+, Pb2+, and Cd2+) under static conditions from single- and multicomponent aqueous solutions by raw and pretreated clinoptilolite. The sorption has an ion-exchange nature and consists of three stages, i.e., the adsorption on the surface of microcrystals, the inversion stage, and the moderate adsorption in the interior of the microcrystal. The finer clinoptilolite fractions sorb higher amounts of the metals due to relative enriching by the zeolite proper and higher cleavage. The slight difference between adsorption capacity of the clinoptilolite toward lead, copper, and cadmium from single- and multicomponent solutions may testify to individual sorption centers of the zeolite for each metal. The decrease of nickel adsorption from multicomponent solutions is probably caused by the propinquity of its sorption forms to the other metals and by competition. The maximum sorption capacity toward Cd2+ is determined as 4.22 mg/g at an initial concentration of 80 mg/L and toward Pb2+, Cu2+, and Ni2+ as 27.7, 25.76, and 13.03 mg/g at 800 mg/L. The sorption results fit well to the Langmuir and the Freundlich models. The second one is better for adsorption modeling at high metal concentrations.

Adsorption↗
PubMed2006

Application of chemometrics in river water classification.

The main aim of this work is focused on water quality classification of the Brda river (Poland) and evaluation of pollution data obtained by the monitoring measurement during the period 1994-2002. The study presents the application of selected chemometric techniques to the pollution monitoring dataset, namely, cluster analysis, principal component analysis, discriminant analysis and factor analysis. The obtained results allowed to determine natural clusters and groups of monitoring locations with similar pollution character and identify important discriminant variables. Chemometric analysis confirmed the classification of water purity of the Brda river made by the Inspection of Environmental Protection but the results showed more differentiation between monitored locations. This enables better evaluation of the water quality in a monitored region. On the basis of the chemometric approach, it was also found that some locations were under the high influence of municipal contamination, and some others under the influence of agriculture (discharges from fields) within the observed time period.

Agriculture↗
PubMed2006

Some remarks on characterization and application of stationary phases for RP-HPLC determination of biologically important compounds.

Biologically active compounds such as vitamins, steroids, nucleosides, peptides and proteins play a very important role in coordinating living organism functions. Determination of those substances is indispensable in pathogenesis. Their complex structure and physico-chemical properties cause many analytical problems. Chromatography is the most common technique used in pharmaceutical and biomedical analysis. The interaction between analyte and stationary phase plays a major role in the separation process. The structure of the packing has a significant influence on the results of the separation process. Various types of spectroscopic techniques, such as nuclear magnetic resonance spectroscopy, infrared spectroscopy, fluorescence spectroscopy and photoacoustic spectroscopy can be useful tools for the characterization of packings. Surface area measurements, elemental analysis, thermal analysis and microcalorimetric measurements are also helpful in this field. Part of the paper contains a description of chromatographic tests used for the determination of column properties. The description of the possibilities of surface characterization is not complete, but is focused on the most popular techniques and practical chromatographic tests. All the presented methods made possible the design and quality control of a new generation stationary phases, which are the future of high-performance liquid chromatography.

Chromatography, High Pressure Liquid↗
PubMed2006

Rapid identification of Escherichia coli and Helicobacter pylori in biological samples by capillary zone electrophoresis.

The differences in surface charge of different bacteria can be exploited for their separation by capillary electrophoresis. However, this method of separation of microorganisms is beset with various drawbacks such as adhesion of bacteria to the fused silica surface or cluster formation. To overcome these phenomena we investigated the addition of poly(ethylene oxide) as a focusing agent to the running buffer and used calcium and myoinositol hexakisphosphate as specific ions that interact with the bacterial surface, changing its electrical properties and electrophoretic mobilities. In the present work, we applied CZE to identification of E. coli in infected urine (direct injection) from patients with urinary tract infections and to identification of Helicobacter pylori, which is a gram-negative bacillus responsible for one of the most common infections found in humans worldwide. Helicobacter pylori colonize the stomach and are responsible for severe diseases of the gastric tract, ranging from chronic gastric ulcer to gastric cancer.

Electrophoresis, Capillary↗
PubMed2006

Influence of stationary phase properties on the separation of ionic liquid cations by RP-HPLC.

Different types of columns with specific structural properties were used for the separation of mixtures of ionic liquid cations. Two of them were home-made packings and the other two were commercial stationary phases. One of the home-made packings contained cholesterol ligands bonded chemically to silica (SG-CHOL) whereas the other one was a mixed stationary phase (SG-MIX) with cyanopropyl, aminopropyl, phenyl, octyl, and octadecyl ligands. RP-18e Innovation ChromolithTM Performance and Macrosphere 300 C4 packings were also used. A comparison of the separation possibilities offered by these columns for the substances in question revealed significant differences in performance. Packings containing surface-bonded functional groups that are able to undergo protonation are not suitable for separation of such compounds under the given analysis conditions (pH = 4). The best results were obtained for two alkyl stationary phases: butyl and octadecyl. Cluster analysis has also been performed for comparison of the ionic liquid cation properties.

Journal Article↗
PubMed2006

Effect of coverage density and structure of chemically bonded silica stationary phases on the separation of compounds with various properties.

The chemical character, geometry, and architecture of chemically formed surface layers determine interactions between stationary phase, analyte, and mobile phase, and therefore the retention mechanisms (partitioning, adsorption, ion exchange, steric exclusion) of separated analytes. These interactions also depend on the structure and chemical character of the solutes and the composition of the mobile phase. High-molecular-weight fullerenes (C60 and C70) and water-soluble selenium-containing peptides (833 and 2607 Da) were used for the evaluation of laboratory-prepared octadecyl stationary phases with high and low coverage density before and after end-capping. The aim of this work was to study differences in surface coverage density and homogeneity and conformational changes of chemically bonded moieties and the influence of these parameters on the separation of mixtures of selenopeptides and fullerenes with significantly different molecular masses. A topographical model of the chemically modified stationary surface is presented.

Amino Acid Sequence↗
PubMed2005

Porous structure of natural and modified clinoptilolites.

The evaluation of the pore-size distribution (PSD) of natural and modified mesoporous zeolites, i.e., clinoptilolites is presented. We demonstrate the SEM results showing that the pores of fracture-type from 25-50 nm to 100 nm in size between clinoptilolite grains, as well as pores between crystal aggregates up to 500 nm in size are present in the studied material. The detailed distribution of pore sizes and tortuosity factor of the above-mentioned materials are determined from the adsorption-desorption isotherms of nitrogen measured volumetrically at 77 K. To obtain the reliable pore size distribution (PSD) of the above-mentioned materials both adsorption and desorption branches of the experimental hysteresis loop are described simultaneously by recently developed corrugated pore structure model (CPSM) of Androutsopoulos and Salmas. Evaluated pore size distributions are characterized by well-defined smooth peaks placed in the region of the mesoporosity. Moreover, the mean pore diameter calculated from the classical static measurement of nitrogen adsorption at 77 K correspond very well to the pore diameters from SEM, showing the applicability of the CPSM for characterization of the porosity of natural zeolites. We conclude that classical static adsorption measurements combined with the proper modeling of the capillary condensation/evaporation phenomena are a powerful method which can be applied for pore structure characterization of natural and modified clinoptilolites.

Microscopy, Electron↗
PubMed2005

Separation of microorganisms using electromigration techniques.

Like other colloidal particles bacteria have a surface charge that originates from the ionization of surface molecules and of the adsorption of ions from solution. Bacterial cell wall and membranes containing numerous proteins, lipid molecules, teichoic acids, lipopolisaccharides which give them characteristic charge. Therefore, bacterial cells undergo electrophoresis in a free solution with their own mobility depending on ionic strength and pH of buffer solution. Various electromigration techniques can be used to separate and determine the intact cells. Successful separation of five species of bacteria was obtained using a trimethylchlorosilane-modified capillary and a divinylbenzene-modified with suppressed EOF over a short distance (8.5 cm). The utilization of coated capillaries prevents adsorption of bacteria to the capillary wall. Another approach is utilization of a dilute dissolved polymer, polyethylene oxide (PEO) in the running buffer as a non-bonded coating for the purpose of altering the EOE These experiment have proved the possibility of diagnosing a variety of diseases and the ability to separate and identify viable cells.

Bacteria↗
PubMed2005

Ammonium sorption from aqueous solutions by the natural zeolite Transcarpathian clinoptilolite studied under dynamic conditions.

The scope of this study is ammonium-ion uptake from synthetic aqueous solutions onto raw and pretreated forms of the natural zeolite Transcarpathian clinoptilolite under dynamic conditions. Hydrogen ions displaced exchangeable cations on the clinoptilolite in distilled water (sodium ions) and hydrochloric acid (sodium, potassium, and calcium ions) and destroyed the zeolite framework structure in the last case. Ammonium uptake onto the zeolite occurs by exchange with Na(+), Ca(2+), and K(+) ions. Although Na(+) ions were observed to be more easily exchanged for both hydrogen and ammonium ions, the role of Ca(2+) ions increased with zeolite saturation by NH(+)(4) ions. The maximum sorption capacity of the clinoptilolite toward NH(+)(4) ions, estimated under dynamic conditions, is significantly higher than that measured under static conditions; proximity of the values of a distribution coefficient and a retardation factor for different conditions (215-265 dm(3)/kg and 979-1107, respectively) allows us to use these parameters to model ammonium uptake onto the clinoptilolite. Slowing down or interruption in filtration resulted in the improvement of ammonium sorption properties of the zeolite. The ammonium removal improves with use of the finer fractions of the clinoptilolite up to 0.35 mm. A recycling study results confirmed the importance of external diffusion for ammonium sorption by the clinoptilolite. Preliminary treatment of the sorbent confirmed the predominant importance of the ion-exchange mechanism. The advantage of prior NaCl treatment of the clinoptilolite in improvement of ammonium removal over the other techniques was shown.

Journal Article↗
PubMed2005

The influence of the mobile phase pH and the stationary phase type on the selectivity tuning in high performance liquid chromatography nucleosides separation.

Analysis of the modified nucleosides is particularly important in the medical area because of a possibility of cancerogenic processes studies. The aim of this work was to study the selectivity tuning of modified nucleosides through the investigations of interactions analyte (modified nucleoside) <==> stationary phase <==> mobile phase. A series of homemade stationary phases with different surface properties has been utilized. All of them contain various interaction sites such as: cholesterol (SG-CHOL); n-acylamide (SG-CHOL, SG-AP); aminopropyl (SG-CHOL, SG-AP, SG-NH2, SG-MIX); cyanopropyl, phenyl, octyl (SG-MIX), octadecyl (SG-MIX, SG-C18) and silanols localized on the silica gel surface of all packings. The attempt to predict the main interactions responsible for the retention between nucleosides and stationary phase ligands was done on the basis of the elemental analysis, and proportional part of an individual ligand bonded to silica surface results. In order to study the influence of different packing types on the analyzed nucleosides retention, the relationship between pH of the mobile phase buffer and the selectivity of a stationary phase was investigated.

Chromatography, High Pressure Liquid↗
PubMed2005

Using gas chromatography for indoor-air quality control in conservation and renovation studios.

Investigations were carried out in the Department of Conservation of Painting and Polychrome Sculpture and in the Screen Printing Studio of the Faculty of Art at Nicolaus Copernicus University. Concentration of the vapours of organic solvents was measured in 2 workshops: the Art Conservation Studio and the Screen Printing Studio. This study attempts to evaluate the work environment in both studios by analysing the concentration of vapour solvents over 5 to 7 years of measurements. Volatile solvents--aliphatic and aromatic hydrocarbons, alcohols, esters and ketones--were detected in investigated workplaces. These compounds have a wide range of applications in cleaning and removing old varnishes, lacquers and paints; inhalation is the main route of exposure. Vapour was collected using an active sampling method.

Air Pollution, Indoor↗
PubMed2004

Study of electroosmotic flow in packed capillary columns.

The aim of the work was to find the relationship between the structure of the stationary phase and the velocity of the electroosmotic flow (EOF) that it can generate. The attention was paid to the dependence of the electroosmotic mobility (microEOF) on such parameters as: (i) coverage density of a series of specially synthesized C18 stationary phases with/without end-capping, with monomeric/polymeric architecture; (ii) the length of the alkyl chain in the alkylamide (AP) bonded phase (the phases studied were AP with: C1, C5, C6, C7, C8, C12 and C18 alkyl chains) and the effect of the presence of amide and residual amine groups; (iii) the effect of the mobile phase composition on the EOF; (iv) the effect of pH on the EOF. The obtained results have shown that there is no direct relationship between silanol activity (Galushko test) and electroosmotic mobility for C18 phases. The deterioration of the EOF has been observed for AP phases at high pH values. This effect has been attributed to the presence of hydrolytic pillow, which is connected with the sorption of water from hydro-organic mobile phases.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2004

Optimization of a matrix solid-phase dispersion method for the determination analysis of carbendazim residue in plant material.

The objective of this paper was to prove that matrix solid-phase dispersion (MSPD) coupled with high performance liquid chromatography (HPLC) and column switching could be used for the determination and quantification of carbendazim residue in plant samples. By comparing results obtained after optimization of the extraction conditions on an acidic silica gel column, it was determined that sorption and retention of carbendazim were achieved via specific interactions. The method of standard additions was used for quantitative analysis. Its performance was evaluated and validated: the detection limit (UV-Vis detection at lambda=279 nm) was 0.02 microg/g, the relative standard deviations (R.S.D.) were between 2.7 and 4.1% and the recoveries were ranging from 84.3 to 90.7% at the 0.04, 0.08 and 0.1 microg/g fortification levels. The method was successfully tested on cereal samples, and the results obtained with the present off-line MSPD-HPLC procedure were found to compare well with those obtained with procedure involving LLE.

Benzimidazoles↗
PubMed2004

Molecularly imprinted polymers: a new tool for separation of steroid isomers.

Molecularly imprinted polymers hold great promise for the separation of chiral compounds. A non-covalent approach to the synthesis of MIPs relies on the presence of specific and non-specific interactions, which lead to the formation of a molecular imprint. The structural differences between 17-alpha-estradiol and 17-beta-estradiol are too small to permit their efficient separation on a MIP prepared with beta-estradiol as a template. Molecular modeling revealed the presence of only one hydrogen bond that differentiates the two isomers.

Chromatography↗
PubMed2003

Study of VOC distribution in citrus fruits by chromatographic analysis.

The contamination of various parts of citrus fruits by toluene (a representative of volatile organic compounds-VOCs) was analyzed. The model of contamination distribution, based on investigations of the sorption and accumulation of toluene in particular parts of citrus fruits was considered. Solvent extraction of components from fruit parts (waxy layer, cuticle, and pulp) was applied. The extracts were analyzed by gas chromatography. The sorption time profiles for such citrus fruits as kumquats and mandarins were determined by plotting the extracted mass, or the relationship C/C(0), versus the sorption time of toluene. After the sorption process the highest concentration of toluene was observed in the flavedo, where the oil glands of kumquats and mandarins are located. The data obtained prove that the high dissolution of aromatic hydrocarbons results from the presence of essential oils in the oil glands. The diffusion coefficients of toluene for the cuticle and pulp of kumquats were also calculated. The results of model investigations were compared with the actual concentration of toluene in kumquats, citrons, mandarins and oranges from outdoor stands and orchards.

Absorption↗