Papers by Bogusław Buszewski
Anal. Methods, 2014
A comparative study has been made of three home-made bonded silica columns for the separation of ... more A comparative study has been made of three home-made bonded silica columns for the separation of the components of bovine milk casein (α-, β- and κ-casein).
Journal of Colloid and Interface Science, 2010
A detailed, molecular-level description of the sorption mechanism in reversed-phase liquid chroma... more A detailed, molecular-level description of the sorption mechanism in reversed-phase liquid chromatography is of great interest to analytical chemists. For this purpose, solvent adsorption in the octadecyl stationary bonded phase was investigated. Preferential adsorption of solvents from an acetonitrile-water and methanol-water mobile phase was measured on a series of non-end-capped octadecyl bonded phases with different coverage densities of bonded ligands using the minor disturbance method. For a comparison, a microcalorimetric study of organic solvent adsorption on the stationary phase was executed. The results from the excess isotherm measurement agree well with the experimental measurement of the heat of immersion of the bonded stationary phases by the test solvents. The microcalorimetric measurement is another method for determination of solvation processes of the stationary phases. Changes of the heat of immersion provide information about the surface accessibility for interaction with solvent molecules. The increase of the stationary phase coverage density reduces the free space between bonded chains and penetration of solvent between organic chains.
Journal of separation science, Jan 23, 2015
A set of seven home-made silica based bonded phases with different functional groups was investig... more A set of seven home-made silica based bonded phases with different functional groups was investigated. Their zeta potential data in methanol and acetonitrile as well as in methanol/water and acetonitrile/water solution were obtained by using a Zetasizer. The influence of polar functional groups on a zeta potential was investigated. The results show that the amines incorporated in the structure of chemically bonded phases of reversed-phase materials are protonated during chromatographic analysis, resulting in changes of the zeta potential from negative to positive values. Acetonitrile causes more negative values and methanol provides positive (or less negative) values of the zeta potential.
Chromatographia, 1998
... [5] L. Bojarski, Chem. Anal. (Warsaw) 42, 193 (1997). [6] M. Jinno, K. Yamamoto, J. Mirocol. ... more ... [5] L. Bojarski, Chem. Anal. (Warsaw) 42, 193 (1997). [6] M. Jinno, K. Yamamoto, J. Mirocol. Sep. 4, 187 (1992). [7] N. Brindle, K. Albert, J. Chromatogr. A. 757, 3 (1997). [8] O. Buszewski, RM Gadzaa-Kopciuch, M. Markuszewski, R. Kaliszan, Anal. Chem. 69, 3277 (1997). ...
Chromatographia, 2001
Summary Retention mechanism, selectivity and physicochemical properties together with theoretica... more Summary Retention mechanism, selectivity and physicochemical properties together with theoretical surface simulation experiments of laboratory-synthesized packing materials for high performance liquid chromatography (HPLC) containing cholesterol molecules immobilized on the high quality silica gel were studied. The chromatographic behavior of the three cholesterol-based columns (SG-CHOL, SG-MIX CHOL/AP and SG-10-CHOL) was examined with special regard to retention and selectivity and compared to reference materials: a typical octadecylsilica column (SG-C18) and an alkylamide bonded phase (SG-AP). Temperature investigations (DSC) and molecular modeling simulations didn't bring an expected confirmation of liquid crystalline properties of materials studied. The observed phase transition was attributed to conformation change within the amide bonding.
Analytical methods
In this report chemometric methodology was utilized in comprehensive column comparative character... more In this report chemometric methodology was utilized in comprehensive column comparative characterization in order to define patterns of similarity and dissimilarity between stationary phases under investigation. A quantitative structure–retention relationship approach was adopted to obtain statistically significant molecular-descriptor-based models describing the retention mechanism of eight ionic liquids in two home-made and five commercially available chromatographic columns. Consequently their retention mechanism was also studied and discussed. Principal component analysis was adopted to reduce the dimensionality of experimental data in order to characterize different stationary phases based on the behavior of ionic liquids. QSRR models together with stationary phase characterization provided reliable information on the properties and characteristics of the studied columns.
Journal of Chromatography A, 2015
The objective of this study was to model the retention of nucleosides and pterins in hydrophilic ... more The objective of this study was to model the retention of nucleosides and pterins in hydrophilic interaction liquid chromatography (HILIC) via QSRR-based approach. Two home-made (Amino-P-C18, Amino-P-C10) and one commercial (IAM.PC.DD2) HILIC stationary phases were considered. Logarithm of retention factor at 5% of acetonitrile (logkACN) along with descriptors obtained for 16 nucleosides and 11 pterins were used to develop QSRR models. We used and compared the predictive performance of three regression techniques: partial least square (PLS), the least absolute shrinkage and selection operator (LASSO), and the LASSO followed by stepwise multiple linear regression. The highest predictive squared correlation coefficient (QLOOCV(2)) in PLS analysis was found for Amino-P-C10 (QLOOCV(2)=0.687) and IAM.PC.DD2 (QLOOCV(2)=0.506) and the lowest for IAM.PC.DD2 (QLOOCV(2)=-0.01). Much higher values were obtained for the LASSO model. The QLOOCV(2) equaled 0.9 for Amino-P-C10, 0.66 for IAM.PC.DD2 and 0.59 for Amino-P-C18. The combination of LASSO with stepwise regression provided models with comparable predictive performance as the LASSO, however with possibility of calculating the standard error of estimates. The use of LASSO itself and in combination with classical stepwise regression may offer greater stability of the developed models thanks to more smooth change of coefficients and reduced susceptibility towards chance correlation. Application of QSRR-based approach, along with the computational methods proposed in this work, may offer a useful approach in the modeling of retention of nucleoside and pterin compounds in HILIC.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences, Jan 7, 2015
Chromatographic properties of two columns was compared: commercial IAM.PC.DD2 that imitates the c... more Chromatographic properties of two columns was compared: commercial IAM.PC.DD2 that imitates the cell membrane and home-made Amino-P-C18 (N,O-dialkylphosphoramidate C18). The comparison has been done by correlation of retention (logkw parameters) of a series of solutes: hydrophobic (alkyl benzene derivatives and PAHs) and polar, with both acidic (flavonoids) and basic (nucleosides and nucleic bases) character. The slope of correlation plots for hydrophobic compounds and polar basic was very close to 1.0 that confirms the chromatographic similarity. Only for flavonoids the slope of correlation plot was 1.5. For hydrophobic compound retention parameters logkw were also correlated with hydrophobic parameter logP with very good determination coefficients.
Annual review of analytical chemistry (Palo Alto, Calif.), 2014
Breath analysis is a young field of research with great clinical potential. As a result of this i... more Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath...
Journal of breath research, 2013
The ChemPro 100i chemical detector (aspiration-type ion mobility spectrometer) was used for the d... more The ChemPro 100i chemical detector (aspiration-type ion mobility spectrometer) was used for the detection of selected volatile organic compounds known to be potential indicators of human presence. The targeted group of compounds mainly comprised ketones (acetone, 2-butanone, 2-pentanone, 3-methyl-2-butanone, 4-heptanone), aldehydes (propanal, pentanal, hexanal, octanal), dimethyl disulfide (DMDS), isoprene and ethanol. Gaseous standards of these compounds were produced from pure substances and analysed using the aspiration ion mobility spectrometry (AIMS) chemical detector. The chemical fingerprints obtained (patterns) were compared to evaluate possible differences in responses. The limits of detection ranged from 5 ppbv for 4-heptanone to 87 ppbv for DMDS, whereas relative standard deviations varied from 1.5% to 5%. Additionally, quantitative AIMS measurements of acetone levels in human breath samples were carried out. The breath acetone levels measured with AIMS ranged from 290 to...
Adsorption of acetonitrile and methanol was measured on non-endcapped and endcapped octadecyl sta... more Adsorption of acetonitrile and methanol was measured on non-endcapped and endcapped octadecyl stationary phases. The results enabled us to characterize the effect of end-capping on the adsorption of the organic modifiers. Our results clearly demonstrate how the endcapping groups modify the chromatographic properties of adsorbents. Differences between solvent adsorption mechanisms are also discussed. Adsorption of acetonitrile is governed by hydrophobic effects whereas methanol is adsorbed by the organic ligand by a hydrophobic interaction and by the residual silanols by hydrogen-bond formation and dipole-dipole interactions.
The excess adsorption isotherms of organic modifiers (methanol and acetonitrile) from water on ch... more The excess adsorption isotherms of organic modifiers (methanol and acetonitrile) from water on chemically bonded stationary phases were studied, using seven different packed columns with different organic ligand lengths from C4 to C30. Isotherms were measured using the minor disturbance method. Excess isotherms can give useful information about the structure of the stationary phase. The amount of “adsorbed” solvent can indicate the type of distribution mechanism.
The chemical and physical properties of the stationary and the mobile phase determine the retenti... more The chemical and physical properties of the stationary and the mobile phase determine the retention and selectivity of the separated molecules in chromatographic process. It should explain the specific and non-specific interactions in the chromatographic system. Special emphasis should be placed on column selection through the adequate choice of column dimensions (diameter and length) and the type of stationary phase with required parameters, which contributes the system effectiveness. However, column effectiveness is unable to guarantee a satisfactory level of substance separation. For this reason, the interactions between the analyte, the stationary and the mobile phase need to be investigated to determine the retention factors of the separated substances and the optimal parameters of the chromatographic system. According to the principles of thermodynamics, in particular molecular interactions, the chromatographic process has to be carried out with a high level of control. This work can be treated a brief tutorial devoted to thermodynamics of liquid chromatography process with a special emphasis on molecular interactions between analyte species and the components of the mobile and stationary phases.
The scope of this study was ammonium ions removal from synthetic aqueous solutions by raw and pre... more The scope of this study was ammonium ions removal from synthetic aqueous solutions by raw and pretreated natural zeolite, Transcarpathian mordenite under static and dynamic conditions. The cation exchange capacity of the Transcarpathian mordenite regarding ammonium ions was evaluated as 1.64 meq/g at 1000 mg/l initial NH 4 -N concentration. The dynamic exchange capacity exceeded one estimated in equilibrium study at the same initial concentration that may be conditioned by the constant removal of ion exchange products. Ammonium uptake rate was controlled by particle diffusion with diffusion coefficients determined in the range of 0.7-3.6 × 10 −12 m 2 /s. Efficiency of ammonium sorption may be improved by slowing down of initial solution rate in the column test and non-significantly by NaCl and HCl pretreatment of the mordenite. Ammonium sorption by the mordenite increased from the coarser to the finer fraction but this dependence became weaker to low flow rates. It was established that hydrogen ions displaced exchangeable cations on the mordenite in distilled water and hydrochloric acid with destroy of the zeolite framework structure in the last case. NH 4 + -ions removal from aqueous solutions occurs mainly by ion exchange with Na + -and Ca 2+ -ions at the practically equal parts of them because of the weakest affinity of the mordenite to these cations.
The scope of this study was adsorption of lindane and aldrin from water solution onto clinoptilol... more The scope of this study was adsorption of lindane and aldrin from water solution onto clinoptilolite rock with the following desorption using n-hexane. Both kinetic and equilibrium tests were conducted. During kinetic experiment the most part of aldrin and a half part of lindane were sorbed during the first hours. The sorption equilibria with removal of 95% of aldrin amount and about 68% of lindane amount have been set in for 48 h. The pseudo-second-order kinetics model gives somewhat better fit to the both pesticides' sorption data that may testify to the complicated and heterogeneous nature of interaction between active zeolite surface and the pesticides polar-dipole centers. OH(-)-groups and the coordinated exchangeable cations are probably the main active positions for the pesticide sorption on the clinoptilolite surface. Equilibrium experiment results show that adsorption isotherms for the low concentrations of lindane and aldrin (10-200 and 3-100 microg/L, respectively) fit well to the Freundlich and the Liner models. Only 10% of lindane sorbed and about 60% of aldrin sorbed were desorbed from the clinoptilolite using n-hexane under static conditions.
In this work, we present the excess isotherm of acetonitrile for stationary phases with different... more In this work, we present the excess isotherm of acetonitrile for stationary phases with different coverage density. Data obtained with the minor disturbance method were compared with 29 Si cross-polarization/magic-angle spinning NMR spectra to find dependence between acetonitrile adsorption on C18 chemically bonded stationary phases and coverage density of stationary phase. The preferential adsorption of acetonitrile on the bonded phase and the adsorption of water on the silica surface can be well correlated with the coverage density.
This contribution presents the possibility of application of natural sorbent (Transcarpathian cli... more This contribution presents the possibility of application of natural sorbent (Transcarpathian clinoptylolite (KL)) for immobilization of selected heavy metals in the sewage sludge. The influence of ion-exchange parameters (e.g. time, amount of zeolite) were discussed. Process of immobilization was performed using a static method (Batch). It was found that best possible conditions for immobilization of heavy metal ions were as follows: zeolite fraction 0.7-1.0 mm, 5 h of shaking, zeolite/sewage sludge ratio 2/98.
Journal of breath research, 2014
Breath analysis is a young field of research with its roots in antiquity. Antoine Lavoisier disco... more Breath analysis is a young field of research with its roots in antiquity. Antoine Lavoisier discovered carbon dioxide in exhaled breath during the period 1777-1783, Wilhelm (Vilém) Petters discovered acetone in breath in 1857 and Johannes Müller reported the first quantitative measurements of acetone in 1898. A recent review reported 1765 volatile compounds appearing in exhaled breath, skin emanations, urine, saliva, human breast milk, blood and feces. For a large number of compounds, real-time analysis of exhaled breath or skin emanations has been performed, e.g., during exertion of effort on a stationary bicycle or during sleep. Volatile compounds in exhaled breath, which record historical exposure, are called the 'exposome'. Changes in biogenic volatile organic compound concentrations can be used to mirror metabolic or (patho)physiological processes in the whole body or blood concentrations of drugs (e.g. propofol) in clinical settings-even during artificial ventilation o...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
• The diatomite modified by the ionic liquids was first synthesized and characterized.
Talanta, 2014
A new construction of split-flow transport-thin fractionation (SPLITT) channel has been developed... more A new construction of split-flow transport-thin fractionation (SPLITT) channel has been developed. The channel is designed to work in full-feed depletion mode. Through the use of fixed and different diameters of outlets, the channel has ability to self-adjust the velocity of sample flow at the outlets. Thus the entire fractionation is achieved with one adjustable parameter, namely the flow rate at the inlet to the channel simple to set by low pulsation pump. Moreover, only one splitter at the end of separation cell was applied to enhance the sample throughput. The system performance was tested with silica particles suspension during both short and long term fractionations. Additionally, natural zeolite was used to check the feasibility of channel to separate other materials. The particle size distribution in obtained fractions and initial suspensions were measured with laser diffraction particle sizer. The results confirm a good resolution of the separation during an hour of permanent use. After 48 h the separation still occurs, however, the resolution is significantly decreasing. Intersection of particle size distribution curves of separated fractions obtained from particle sizer can be used to check an agreement between theoretical and practical value of cut-off diameter.
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Papers by Bogusław Buszewski