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1.

001-es BibID:BIBFORM082768
Első szerző:Andrási Melinda (gyógyszerész)
Cím:Study on repeatability of the determination of temozolomide by micellar electrokinetic capillary chromatography using internal standards / Andrási Melinda, Zékány László, Gáspár Attila
Dátum:2015
ISSN:1061-9348
Megjegyzések:This paper demonstrates the study of the use of single or multiple (2?4) internal standards for the improvement of the repeatability of the micellar electrokinetic capillary chromatographic measurements of temozolomide in model solution and in serum. The dimethylformamide, dimethylsulfoxide, paracetamol and benzyl alcohol were selected as internal standards. The best precision data (RSD less than 0.036%) of the migration times could be reached with two internal standards applying weighted correction according to the distance of the internal standards from the analyte. We also investigated the effects of the use of new capillaries, buffer renewal and postcondition procedures on the repeatability.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
internal standard
precision
temozolomide
MEKC
Megjelenés:Journal Of Analytical Chemistry. - 70 : 11 (2015), p. 1360-1367. -
További szerzők:Zékány László (1948-) (vegyész) Gáspár Attila (1970-) (vegyész, kémikus)
Pályázati támogatás:PD 83071
OTKA
RH/885/2013)
Egyéb
TÁMOP-4.2.2.A-11/KONV-2012-0043
TÁMOP
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2.

001-es BibID:BIBFORM064107
035-os BibID:(WoS)000379001100013 (Scopus)84970973735
Első szerző:Antal Borbála (vegyész)
Cím:Rapid detection of hazardous chemicals in textiles by direct analysis in real-time mass spectrometry (DART-MS) / Borbála Antal, Ákos Kuki, Lajos Nagy, Tibor Nagy, Miklós Zsuga, Sándor Kéki
Dátum:2016
ISSN:1618-2642 1618-2650
Megjegyzések:Abstract Residues of chemicals on clothing products wereexamined by direct analysis in real-time (DART) mass spectrometry.Our experiments have revealed the presence of morethan 40 chemicals in 15 different clothing items. The identificationwas confirmed by DART tandem mass spectrometry(MS/MS) experiments for 14 compounds. The most commonlydetected hazardous substances were nonylphenolethoxylates (NPEs), phthalic acid esters (phthalates), aminesreleased by azo dyes, and quinoline derivates. DART-MS wasable to detect NPEs on the skin of the person wearing theclothing item contaminated by NPE residuals. Automated dataacquisition and processing method was developed and testedfor the recognition of NPE residues thereby reducing the analysistime
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Direct analysis in real-time tandemmass spectrometry (DART-MS; DART-MS/MS)
Hazardous substances
Textile articles
Nonylphenol ethoxylate (NPE)
Phthalic acid ester (phthalate)
Quinolines
Megjelenés:Analytical And Bioanalytical Chemistry. - 408 : 19 (2016), p. 5189-5198. -
További szerzők:Kuki Ákos (1966-) (villamosmérnök) Nagy Lajos (1979-) (vegyész) Nagy Tibor (1988-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:K-101850
OTKA
TÁMOP-4.2.2.A-11/1/KONV-2012-0036
TÁMOP
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3.

001-es BibID:BIBFORM094364
Első szerző:Balogh Ioseph S.
Cím:A simple method of boron determination in mineral waters using Victoria blue 4R / Ioseph S. Balogh, Vasil Andruch, Mihály Kádár, Ferenc Billes, József Posta, Eva Szabová
Dátum:2009
ISSN:0306-7319
Megjegyzések:The reaction of the tetrafluoroborate anion with Victoria blue 4R (VB4R) reagent was investigated, and a new, simple, rapid and sensitive method was developed for the spectrophotometric determination of boron. The method is based on the reaction of boric acid with fluoride, which forms the tetrafluoroborate anion, and that is followed by the extraction of [image omitted] with VB4R into benzene and subsequent spectrophotometric detection. The optimum conditions for the conversion of boron to tetrafluoroborate anion as well as for complex formation and extraction of [image omitted] with VB4R were found. The molar absorptivity of the investigated complex is 9.6 104 L mol-1 cm-1 at 610 nm. The absorbance of the coloured extracts obeys Beer's law in the range 0.03-0.55 mg L-1 of B(III). The limit of detection calculated from a blank test (n = 10; P = 0.95) based on 3 s is 0.02 mg L-1 of B(III). Under appropriate extraction conditions, the majority of metals (excluding probably tantalum and some others) did not form extractable fluoride complexes with VB4R. Therefore, the presence of small quantities of metals should not interfere with the determination of boron in the presence of a sufficient surplus of fluoride. Exceptions, however, are metal ions such as Sn(IV), Ti(IV), Sn(II), Zr(IV), Hg(II), Hg(I), Tl(I), etc., which strongly hydrolysed under experimental conditions. Some anions formed complexes with the cation of VB4R and are easily extractable using benzene. Examples of such ions are [image omitted], I-, SCN-, Br-, bromate, chlorate, iodate and perrhenate. These anions strongly interfere with boron determination and therefore must first be extracted with VB4R before boron determination. The boron must then be converted to [image omitted] and extracted with VB4R into benzene for determination. The Cl-, [image omitted], [image omitted], CH3COO- and [image omitted] anions are extracted in very small amounts or not at all, and do not interfere with boron determination. The reaction mechanism was also discussed. Quantum chemical calculations were carried out for VB4R, and the optimised molecular structure and atomic net charges were calculated. The possible position of the protonation of VB4R as well as the possible position for dipole-ion interaction (associate building) between the reagent and the [image omitted] anion was predicted. The method was used for the determination of boron in commercial brand mineral waters.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
boron
determination
mineral waters
Victoria blue 4R
spectrophotometry
Megjelenés:International Journal of Environmental Analytical Chemistry. - 89 : 6 (2009), p. 449-459. -
További szerzők:Andruch, Vasil Kádár Mihály Billes Ferenc Posta József (1948-) (vegyész, analitikus) Szabová, Eva
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4.

001-es BibID:BIBFORM085799
Első szerző:Gáspár Attila (vegyész, kémikus)
Cím:Beam-injection flame-furnace atomic-absorption spectrometry (BIFF-AAS) with low-pressure sample-jet generation / Attila Gáspár, Harald Berndt
Dátum:2002
ISSN:1618-2642 1618-2650
Megjegyzések:Flame-furnace AAS (FF-AAS) comprises two individual, recently developed FAAS techniques remarkable for their high power of detection and the small amounts of sample required. One of these techniques is beam-injection flame-furnace AAS (BIFF-AAS), whereby the sample is introduced into a flame-heated atomization cell as a high-speed liquid jet. For the first time this sample-introduction beam has been generated at low pressure by use of a peristaltic pump and a special micro channel smooth jet nozzle developed for this application. Compared with standard FAAS a 7- to 17-fold improvement in the power of detection was obtained for six elements (Ag, Cd, Hg, Pb, Se, and Zn). The relative standard deviation (N=15) was between 0.7% and 3.4%. Sample volumes between 10 mL and 1 mL have been investigated. The applicability of the peristaltic pump for beam generation enables an optimum sampling mode for a variety of analytical tasks (continuous sample uptake, manual or automated, or different flow-injection modes). The method can also be regarded as a simple, effective interface between FIA techniques and flame AAS.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Flame AAS
Flame furnace AAS
Beam injection
Micro samples
Sample-jet generation
Megjelenés:Analytical and Bioanalytical Chemistry. - 372 : 5-6 (2002), p. 695-699. -
További szerzők:Berndt, Harald
Pályázati támogatás:FKFP 23/2001
Egyéb
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5.

001-es BibID:BIBFORM085775
Első szerző:Gáspár Attila (vegyész, kémikus)
Cím:Analysis of submicroliter samples using micro thermospray flame furnace atomic absorption spectrometry / Attila Gáspár, Éva Széles, Harald Berndt
Dátum:2002
ISSN:1618-2642 1618-2650
Megjegyzések:A recently described thermospray flame furnace atomic absorption spectrometric (TS-FF-AAS) system has been modified in order to extend the applicability of the method for the determination of elemental traces in very small sample volumes (microliter or submicroliter). As an easily available, effective thermospray vaporizer, a fused silica capillary was used and the liquid sample was transported by 1 MPa (10 bar) gas pressure delivered by a standard gas cylinder. A 0.3 ?L sample volume can be analyzed with a higher power of detection than using 3 orders of magnitude larger sample volumes with conventional flame atomic absorption spectrometry. The relative standard deviations (N=12) for 0.3 ?L volumes and 5 ?g/mL Pb samples amount to 3.1% and 3.8% in signal height and signal area, respectively. The detection limit was found to be 69 ng/mL. Initial experiments with other elements (Cd, Hg, Tl, Zn) led to similar results.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Thermospray
FFAAS
Spectrometry
atomic absorption
microthermospray
Megjelenés:Analytical and Bioanalytical Chemistry. - 372 : 1 (2002), p. 136-140. -
További szerzők:Széles Éva (1979-) (vegyész) Berndt, Harald
Pályázati támogatás:FKFP 23/2001
Egyéb
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6.

001-es BibID:BIBFORM010519
Első szerző:Gáspár Attila (vegyész, kémikus)
Cím:Application of external micro-spectrophotometric detection to improve sensitivity on microchips / Attila Gáspár, István Bácsi, Erika F. Garcia, Mihály Braun, Frank A. Gomez
Dátum:2009
ISSN:1618-2642
Megjegyzések:The goal of this work was to increase the sensitivity of a UV-Vis spectrophotometer by decreasing the background noise and lengthening the optical path. A microphotometer has been modified to precisely select very small parts of a microfluidic channel pattern of a chip and to measure light absorbance on a magnified area of the selected part of the channel. The viability of combining a projection microscope and a spectrophotometer for external absorbance measurements on disposable PDMS chips was studied. Besides the external direct detection above a microfluidic channel, the optical pathlength was lengthened by detecting in the region of the perpendicular exit port. Increasing the cross-sectional area of the zone of irradiation improved the signal-to-noise ratio and the limits of detection (LOD).
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Analytical and Bioanalytical Chemistry. - 395 : 2 (2009), p. 473-478. -
További szerzők:Bácsi István (1977-) (biológus) Garcia, Erika F. Braun Mihály (1966-) (vegyész, analitikus) Gomez, Frank A.
Internet cím:DOI
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7.

001-es BibID:BIBFORM003011
035-os BibID:(WoS)000250173200041 (Scopus)35448976947
Első szerző:Gáspár Attila (vegyész, kémikus)
Cím:Fabrication of fritless chromatographic microchips packed with conventional reversed-phase silica particles / Attila Gaspar, Menake E. Piyasena, and Frank A. Gomez
Dátum:2007
ISSN:0003-2700
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Analytical Chemistry. - 79 : 20 (2007), p. 7906-7909. -
További szerzők:Piyasena, Menake E. Gomez, Frank A.
Internet cím:elektronikus változat
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8.

001-es BibID:BIBFORM106221
035-os BibID:(WoS)000620922300005 (Scopus)85100650802
Első szerző:Gyöngyösi Tamás (vegyész)
Cím:Expedited Nuclear Magnetic Resonance Assignment of Small- to Medium-Sized Molecules with Improved HSQC-CLIP-COSY Experiments / Tamás Gyöngyösi, István Timári, Davy Sinnaeve, Burkhard Luy, Katalin E. Kövér
Dátum:2021
ISSN:0003-2700
Megjegyzések:Resonance assignment is a pivotal step for any nuclear magnetic resonance (NMR) analysis, such as structure elucidation or the investigation of protein-ligand interactions. Both H-1-C-13 heteronuclear single quantum correlation (HSQC) and H-1 -H-1 correlation spectroscopy (COSY) two-dimensional (2D) experiments are invaluable for H-1 NMR assignment, by extending the high signal dispersion of C-13 chemical shifts onto H-1 resonances and by providing a high amount of through-bond connectivity information, respectively. The recently introduced HSQC-CLIP(Clean In-Phase)-COSY method combines these two experiments, providing COSY correlations along the high-resolution C-13 dimension with clean in-phase multiplets. However, two experiments need to be recorded to unambiguously identify COSY cross-peaks. Here, we propose novel variants of the HSQC-CLIP-COSY pulse sequence that edit cross-peak signs so that direct HSQC responses can be distinguished from COSY relay peaks, and/or the multiplicities of the C-13 nuclei are reflected, allowing the assignment of all the peaks in a single experiment. The advanced HSQC-CLIP-COSY variants have the potential to accelerate and simplify the NMR structure-elucidation process of both synthetic and natural products and to become valuable tools for high-throughput computer-assisted structure determination.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
NMR spektroszkópia
szerkezetvizsgálat
CLIP-COSY
HSQC
NMR spectroscopy
peptide
structure elucidation
Megjelenés:Analytical Chemistry. - 93 : 6 (2021), p. 3096-3102. -
További szerzők:Timári István (1989-) (vegyész) Sinnaeve, Davy Luy, Burkhard Kövér Katalin, E. (1956-2023) (vegyész)
Pályázati támogatás:NKFI/OTKA NN 128368
OTKA
NKFI/OTKAPD 135034
OTKA
GINOP-2.3.3-15-2016-00004
GINOP
GINOP-2.3.2-15-2016-00008
GINOP
BO/00372/20/7
MTA
ÚNKP-20-5-DE-262
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9.

001-es BibID:BIBFORM068812
035-os BibID:(WoS)000401408300008 (Scopus)85015170172
Első szerző:Kecskeméti Ádám (vegyész)
Cím:Development of an enzymatic reactor applying spontaneously adsorbed trypsin on the surface of a PDMS microfluidic device / Adam Kecskemeti, Jozsef Bako, Istvan Csarnovics, Eva Csosz, Attila Gaspar
Dátum:2017
ISSN:1618-2642 1618-2650
Megjegyzések:Herein, a microfluidic device (MD) containing immobilized trypsin for rapid and efficient proteolysis was described. Trypsin was immobilized via non-specific protein adsorption onto the hydrophobic poly(dimethylsiloxane) (PDMS) channel wall of the MD. Peptide mapping of bovine serumalbumin (BSA) samples was carried out to estimate the stability of trypsin adsorbed on PDMS surface. Peptide maps of BSA samples were obtained by capillary zone electrophoresis (CZE), the RSD% for migration times were under 1%. Several proteins (hemoglobin, myoglobin, lysozyme, and BSA) in a wide molecular size range (15?70 kDa) were digested efficiently with ?50 s contact time. The number of separated peaks correlated well with the expected number of peptides formed in the complete tryptic digestion of the proteins. Peptide mass fingerprinting of BSA and human serum was carried out.Trypsin retained its activity for 2 h; within this period, theMDcan be used for multiple digestions. The main properties of this device are simple channel pattern, simple immobilization procedure, regenerability, and disposability;all these features make this MD one of the simplest yet applicable enzymatic microreactors.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Immobilization
Trypsin
Digestion
Peptide mapping
Enzyme reactor
Microfluidic device
Megjelenés:Analytical and Bioanalytical Chemistry. - 409 : 14 (2017), p. 3573-3585. -
További szerzők:Bakó József (1981-) (vegyész) Csarnovics István (1986-) (fizikus) Csősz Éva (1977-) (biokémikus, molekuláris biológus) Gáspár Attila (1970-) (vegyész, kémikus)
Pályázati támogatás:OTKA-111932
OTKA
GINOP-2.3.2-15-2016-00008
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
NTP- EFÖ-P-15-0003
Egyéb
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10.

001-es BibID:BIBFORM074022
035-os BibID:(WoS)000432478600005 (Scopus)85047314302
Első szerző:Kiss Árpád
Cím:Fabrication of a Microfluidic Flame Atomic Emission Spectrometer: a Flame-on-a-Chip / Kiss Árpád, Gáspár Attila
Dátum:2018
ISSN:0003-2700
Megjegyzések:This work demonstrates for the first time the fabrication of a microfluidic flame atomic emission spectrometer (FAES), which incorporates a microburner and flame (flame-on-a-chip). An essential part of the device is a thermospray system applied for effective sample introduction, which is more easily miniaturizable and integrable than the conventional nebulization methods. The merits and limitations of the microfluidic flame atomic emission device were demonstrated and discussed. Using a commercial cigarette lighter including butane gas, the flame temperature made the analysis of the most easily excitable alkali metals possible. The calibration diagrams for Li, Na, and K showed proper linearity in the range of 5-100 mg/L. The analytical applicability of the microfluidic FAES device was tested by analyzing various real samples.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Analytical Chemistry. - 90 : 10 (2018), p. 5995-6000. -
További szerzők:Gáspár Attila (1970-) (vegyész, kémikus)
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11.

001-es BibID:BIBFORM079540
035-os BibID:(WoS)000411709000011 (Scopus)85027340671
Első szerző:Kuki Ákos (villamosmérnök)
Cím:Screening of additives and other chemicals in polyurethanes by direct analysis in real time mass spectrometry (DART-MS) / Ákos Kuki, Lajos Nagy, Tibor Nagy, Miklós Zsuga, Sándor Kéki
Dátum:2017
ISSN:1618-2642 1618-2650
Megjegyzések:Direct analysis in real time mass spectrometry (DART-MS) was used to characterize commercial polyurethane (PUR) samples without sample pretreatment. More than 50 substances, such as catalysts, stabilizers, antioxidants, flame retardants, plasticizers, chain extenders, chain terminators, polyols, solvents, degradation products and contaminants, a few of them presumably toxic, were detected and identified in 18 PUR items. The identification of 16 compounds was further confirmed by DART MS/MS experiments. Catalysts were the largest class of compounds detected in the PURs by DART-MS. In each of the 18 PUR samples, at least one catalyst residue was identified. In addition, DARTMS was able to detect the migration of hazardous chemicals from the PURs to other objects. The collision-induced dissociation (CID) properties of two PUR catalysts, such as the protonated bis[2-(dimethylamino)ethyl] ether (DMAEE) and the protonated 2,2-dimorpholinodiethylether (DMDEE), as well as those of two PUR antioxidants (Antioxidant 1135 and Antioxidant 1076), were explored.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Polymers
Catalysts
Mass spectrometry
Megjelenés:Analytical And Bioanalytical Chemistry. - 409 : 26 (2017), p. 6149-6162. -
További szerzők:Nagy Lajos (1979-) (vegyész) Nagy Tibor (1988-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:GINOP-2.3.2-15-2016-00041
GINOP
ÚNKP-16-3
Egyéb
K-116465
egyéb
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12.

001-es BibID:BIBFORM018657
035-os BibID:(WoS)000275379300019 (Scopus)77949790049
Első szerző:Memboeuf, Antony
Cím:Size Effect on Fragmentation in Tandem Mass Spectrometry / Antony Memboeuf, Andreas Nasioudis, Sergio Indelicato, Ferenc Pollreisz, Ákos Kuki, Sándor Kéki, Oscar F. van den Brink, Károly Vékey, László Drahos
Dátum:2010
ISSN:0003-2700
Megjegyzések:The collision energy or collision voltage necessary to obtain 50% fragmentation (characteristic collision energy/voltage, CCE or CCV) has been systematically determined for different types of molecules [poly(ethylene glycols) (PEG), poly(tetrahydrofuran) (PTHF), and peptides] over a wide mass (degrees of freedom) range. In the case of lithium-cationized PEGs a clear linear correlation (R(2) > 0.996) has been found between CCE and precursor ion mass on various instrument types up to 4.5 kDa. A similar linear correlation was observed between CCV and the mass-to-charge ratio. For singly and multiply charged polymers studied under a variety of experimental conditions and on several instruments, all data were plotted together and showed correlation coefficient R(2) = 0.991. A prerequisite to observe such a good linear correlation is that the energy and entropy of activation in a class of polymers is likely to remain constant. When compounds of different structure are compared, the CCV will depend not only on the molecular mass but the activation energy and entropy as well. This finding has both theoretical and practical importance. From a theoretical point of view it suggests fast energy randomization up to at least 4.5 kDa so that statistical rate theories are applicable in this range. These results also suggest an easy method for instrument tuning for high-throughput structural characterization through tandem MS: after a standard compound is measured, the optimum excitation voltage is in a simple proportion with the mass of any structurally similar analyte at constant experimental conditions.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Surface-induced dissiciation
Protonated leucine-enkephalin
Electron-capture dissociation
Polyethylene-glycol
Internal energy
Collisional activation
Gas-phase
Covalent attachment
Nonergodic process
Small peptides
Megjelenés:Analytical Chemistry. - 82 : 6 (2010), p. 2294-2302. -
További szerzők:Nasioudis, Andreas Indelicato, Sergio Pollreisz Ferenc Kuki Ákos (1966-) (villamosmérnök) Kéki Sándor (1964-) (polimer kémikus) Brink, Oscar F. van den Vékey Károly Drahos László
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