TY - JOUR AU - Szerencsés, Dénes AU - Sepsey, Annamária AU - Felinger, Attila TI - Correctness of the van 't Hoff analysis for homogeneous or heterogeneous retention JF - JOURNAL OF CHROMATOGRAPHY A J2 - J CHROMATOGR A VL - 1709 PY - 2023 PG - 9 SN - 0021-9673 DO - 10.1016/j.chroma.2023.464380 UR - https://m2.mtmt.hu/api/publication/34152053 ID - 34152053 N1 - Funding Agency and Grant Number: New National Excellence Program of the Ministry for Culture and Innovation [K143916, UNKP-22-3]; Gedeon Richter's Talentum Foundation in framework of Gedeon Richter Excellence PhD Scholarship of Gedeon Richter Plc.; NKFIH OTKA [K143916] Funding text: Supported by the UNKP-22-3 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund. The scientific work and results published in this article were reached with the sponsorship of Gedeon Richter's Talentum Foundation in framework of Gedeon Richter Excellence PhD Scholarship of Gedeon Richter Plc. This work was also supported by the NKFIH OTKA grant K143916. The authors thank Dr. Tivadar Farkas for the generous gift of the Phenomenex columns used in the experiments. LA - English DB - MTMT ER - TY - JOUR AU - Kazmouz, Muhamad Yahia AU - Felinger, Attila TI - The Competitive Adsorption of Water and Methanol on a Hybrid Silica Stationary Phase in Supercritical Fluid Chromatography JF - SEPARATIONS J2 - SEPARATIONS VL - 10 PY - 2023 IS - 9 PG - 13 SN - 2297-8739 DO - 10.3390/separations10090492 UR - https://m2.mtmt.hu/api/publication/34135268 ID - 34135268 N1 - ISSN:2297-8739 AB - This study investigates the adsorption of methanol, water, and their mixture in a hybrid silica stationary phase with supercritical carbon dioxide as a mobile phase in supercritical fluid chromatography (SFC). The adsorption isotherms of methanol and water were determined by two dynamic methods: the elution by characteristic point (ECP) method and the inverse method (IM). Both the single-component and competitive bi-Langmuir models were pre-selected for the inverse method. The initial parameters of the single-component isotherm for both methanol and water were estimated with the ECP method by fitting the experimental data to the bi-Langmuir isotherm model. Then, using the inverse method, we refined the single-component isotherm parameter values, which were then further used for determining the competitive isotherm of the methanol–water mixture. The elution profile of the (methanol–water) mixture sample was calculated by the equilibrium-dispersive (ED) model. The results indicated that there is a good agreement between the experimental band profile and the calculated band profile, which was obtained from the parameters of the competitive bi-Langmuir isotherm model, revealing a competition between methanol and water to reach the adsorption sites. Furthermore, the saturation capacity of the adsorption sites in the stationary phase decreased in the case of the mixture sample compared to those for the single-component sample. LA - English DB - MTMT ER - TY - JOUR AU - Sepsey, Annamária TI - An Adventurous Journey Around the Thermodynamics of Liquid Chromatography JF - LC GC NORTH AMERICA: SOLUTION FOR SEPARATION SCIENTISTS J2 - LC GC N AM VL - 40 PY - 2022 IS - 12 SP - 584 EP - 586 PG - 3 SN - 1527-5949 DO - 10.56530/lcgc.na.qk2090y9 UR - https://m2.mtmt.hu/api/publication/33567577 ID - 33567577 LA - English DB - MTMT ER - TY - JOUR AU - Rédei, Csanád AU - Felinger, Attila TI - The impact of placement, experimental conditions, and injections on mass flow measurements in supercritical fluid chromatography. JF - JOURNAL OF CHROMATOGRAPHY A J2 - J CHROMATOGR A VL - 1668 PY - 2022 PG - 7 SN - 0021-9673 DO - 10.1016/j.chroma.2022.462919 UR - https://m2.mtmt.hu/api/publication/32729411 ID - 32729411 AB - In supercritical fluid chromatography (SFC), the variation of pressure, temperature and volumetric flow-rate is most noticeable when the mobile phase contains only neat carbon dioxide. This can be explained by the compressibility of CO2 and introduces several difficulties to the work of chromatographers. The only flow parameter that is considered to be constant across the SFC system is the mass flow-rate. It has been shown that the Coriolis flow meter (CFM) provides different types of information depending on its placement in the instrument. Therefore, the goal of this paper is to investigate several factors affecting the variation of mass flow-rate in SFC, including four different configurations around the column, four sets of experimental conditions along with two columns and a zero-volume union. The effect of disturbances introduced by injections are studied as well. The results show different mass flow-rates when taken at the inlet or the outlet of the column. In addition, different columns produced different tendencies of variations. Study of the injections showed that the initial severe drop of mass flow is reduced when the averages are taken until the elution times of the chosen compounds. Additional testing related to possible leaks and CFM calibration showed that even if all standard operating procedures are strictly followed, reproducibility of the mass-flow rate can still be an issue. LA - English DB - MTMT ER - TY - JOUR AU - Kazmouz, Muhamad Yahia AU - Rédei, Csanád AU - Felinger, Attila TI - The adsorption of methanol on reversed phase stationary phases in supercritical fluid chromatography JF - JOURNAL OF CHROMATOGRAPHY A J2 - J CHROMATOGR A VL - 1653 PY - 2021 PG - 8 SN - 0021-9673 DO - 10.1016/j.chroma.2021.462386 UR - https://m2.mtmt.hu/api/publication/32095193 ID - 32095193 LA - English DB - MTMT ER - TY - JOUR AU - Zelenyánszki, Dóra AU - Felinger, Attila TI - The impact of column hardware on efficiency in liquid chromatography (LC) JF - LC GC EUROPE J2 - LC GC EUR VL - 33 PY - 2020 IS - 10 SP - 498 EP - 504 PG - 7 SN - 1471-6577 UR - https://m2.mtmt.hu/api/publication/31626827 ID - 31626827 N1 - Funding Agency and Grant Number: NKFIH OTKA [K125312]; New National Excellence Program of the Ministry of Human Capacities [UNKP-19-3-I-PTE-119] Funding text: The work was supported by the NKFIH OTKA grant K125312. The work was also supported by the UNKP-19-3-I-PTE-119 New National Excellence Program of the Ministry of Human Capacities. The authors thank Waters Corporation for the generous gift of the columns used in the experiments. The authors are grateful to Laszlo Seress and Hajnalka Abraham (Central Electron Microscope Laboratory, University of Pecs) for the electron microscopic measurements. LA - English DB - MTMT ER - TY - JOUR AU - Matarashvili, Iza AU - Chelidze, Aluda AU - Dolidze, Gizo AU - Kobidze, Giorgi AU - Zaqashvili, Nino AU - Dadianidze, Alexandre AU - Bacskay, Ivett Orsolya AU - Felinger, Attila AU - Farkas, Tivadar AU - Chankvetadze, Bezhan TI - Separation of enantiomers of chiral basic drugs with amylose- and cellulose- phenylcarbamate-based chiral columns in acetonitrile and aqueous-acetonitrile in high-performance liquid chromatography with a focus on substituent electron-donor and electron-acceptor effects JF - JOURNAL OF CHROMATOGRAPHY A J2 - J CHROMATOGR A VL - 1624 PY - 2020 PG - 11 SN - 0021-9673 DO - 10.1016/j.chroma.2020.461218 UR - https://m2.mtmt.hu/api/publication/31321664 ID - 31321664 N1 - Funding Agency and Grant Number: NKFIH OTKAOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [K125312] Funding text: The work was in part supported by the NKFIH OTKA grant K125312 LA - English DB - MTMT ER - TY - JOUR AU - Sepsey, Annamária AU - Horváth, Éva AU - Catani, Martina AU - Felinger, Attila TI - The correctness of van ’t Hoff plots in chiral and achiral chromatography JF - JOURNAL OF CHROMATOGRAPHY A J2 - J CHROMATOGR A VL - 1611 PY - 2020 PG - 7 SN - 0021-9673 DO - 10.1016/j.chroma.2019.460594 UR - https://m2.mtmt.hu/api/publication/30859244 ID - 30859244 N1 - Funding Agency and Grant Number: NKFIH OTKA [K125312]; New National Excellence Program of the Ministry of Human Capacities [UNKP-18-3-I-PTE-190]; European Union; European Social Fund [EFOP-3.6.1.-16-2016-00004]; [GINOP-2.3.2-15-2016-00022] Funding text: The work was supported by the NKFIH OTKA grant K125312 and by grant GINOP-2.3.2-15-2016-00022. The work was also supported by the UNKP-18-3-I-PTE-190 New National Excellence Program of the Ministry of Human Capacities.; The project has been supported by the European Union, co-financed by the European Social Fund Grant no.: EFOP-3.6.1.-16-2016-00004 entitled by Comprehensive Development for Implementing Smart Specialization Strategies at the University of Pecs. AB - van ’t Hoff plots (logarithm of the retention factor, ln k, vs. the reciprocal of absolute temperature, 1/T) are commonly used in chromatographic studies to characterize the retention mechanisms based on the determined enthalpy (ΔH∘) and entropy (ΔS∘) change of analyte adsorption. In reversed phase liquid chromatography, the thermodynamic parameters could help to understand the retention mechanism. In chiral chromatography, however, the conclusions drawn based on van ’t Hoff plots can be deceptive because several different types of adsorption sites are present on the surface of stationary phase. The influence of heterogeneity, however, cannot be studied experimentally. In this study, we employed two reversed phase columns with different retention mechanisms to show that by serially coupling the columns, the obtained thermodynamic parameters are not related to the results obtained on the respective individual columns. Furthermore, our results show that the experimental conditions – such as flow-rate or choice of instrument – will strongly influence the calculated enthalpy and entropy values. LA - English DB - MTMT ER - TY - CHAP AU - Simon, József AU - Rédei, Csanád AU - Zelenyánszki, Dóra AU - Felinger, Attila ED - Balogh, András ED - Klein, Mónika TI - Komplex mintakeverékből származó komponensek eredetének meghatározása és vizsgálata alterációs analízissel T2 - Műszaki Kémiai Napok 2019: Chemical Engineering Conference 2019 PB - Pannon Egyetem CY - Veszprém SN - 9789633961216 PY - 2019 SP - 75 EP - 75 PG - 1 UR - https://m2.mtmt.hu/api/publication/32012564 ID - 32012564 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Zelenyánszki, Dóra AU - Mester, Adrienn AU - Felinger, Attila TI - Flow-Reversal Experiments with Macromolecules to Measure Column End Efficiency and Bed Heterogeneity JF - CHROMATOGRAPHIA J2 - CHROMATOGRAPHIA VL - 82 PY - 2019 IS - 9 SP - 1303 EP - 1309 PG - 7 SN - 0009-5893 DO - 10.1007/s10337-019-03759-0 UR - https://m2.mtmt.hu/api/publication/30731628 ID - 30731628 N1 - * Megosztott szerzőség LA - English DB - MTMT ER -