• MeSH
• chromatografie na tenké vrstvě MeSH
• chromatografie plynová MeSH
• equilenin analogy a deriváty   analýza   chemie   MeSH
• estrogeny analýza   chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

The availability of ionic liquids (ILs) in wide areas of application often results in the requirement on their determination. The attention is also often focused on the knowledge of hydrophobicity as it plays a key role in the biological effects, in the assessment of environmental risk and in the prediction of the fate of chemicals in the environment and of its influence on retention in RP HPLC. One can get information regarding hydrophobicity and retention mechanism if quantitative structure-retention relationships (QSRRs) are identified. The QSRRs were derived for logarithms of retention factors extrapolated to a pure water (or aqueous buffer) eluent, log k(w), determined for the pyridinium and imidazolium ionic liquid (IL) cations on two C8 (Supelcosil LC-8-DB, Symmetry C8) and two C18 (ACE 5 C18, Symmetry C18) stationary phases with isocratic elution by a mobile phase consisting of acetonitrile/40 mM phosphate buffer. The analyses of ILs were performed at a flow rate of 1 mL min(-1) with UV detection at 218 nm. The QSRRs were derived based on the retention parameters determined experimentally and the structural descriptors of test analytes from molecular modeling. Separations of ILs were obtained with aqueous acetonitrile buffered at pH 3.55 mobile phases. The statistically most significant two-parameter QSRR regression equations related log k(w) to the solvent accessible surface (SAS) of the analytes and the differences in the energies of the highest occupied and the lowest unoccupied molecular orbitals (diffHL). These equations were especially good in case of columns with the highest carbon loads and larger specific surface areas, i.e. Symmetry C18 and Symmetry C8. On the other hand, the column ACE 5 C18 appeared to produce the best quality separations of the ILs studied. The QSRRs derived in the research shed light on the molecular mechanism of HPLC separation of ILs and helped to predict their relative separations.

• MeSH
• chemické modely MeSH
• chromatografie s reverzní fází metody   MeSH
• hydrofobní a hydrofilní interakce MeSH
• iontové kapaliny chemie   MeSH
• kationty chemie   MeSH
• molekulární struktura MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We studied sequence-dependent retention properties of synthetic 5'-terminal phosphate absent trinucleotides containing adenine, guanine and thymine through reversed-phase liquid chromatography (RPLC) and QSRR modelling. We investigated the influence of separation conditions, namely mobile phase composition (ion interaction agent content, pH and organic constituent content), on sequence-dependent separation by means of ion-interaction RPLC (II-RPLC) using two types of models: experimental design-artificial neural networks (ED-ANN), and linear regression based on molecular dynamics data. The aim was to determine those properties of the above-mentioned analytes responsible for the retention dependence of the sequence. Our results show that there is a deterministic relation between sequence and II-RPLC retention properties of the studied trinucleotides. Further, we can conclude that the higher the content of ion-interaction agent in the mobile phase, the more prominent these properties are. We also show that if we approximate the polar component of solvation energy in QSRR by the electrostatic work in transferring molecules from vacuum to water, and the non-polar component by the solvent accessible surface area, these parameters best describe the retention properties of trinucleotides. There are some exceptions to this finding, namely sequences 5'-NAN-3', 5'-ANN-3', 5'-TGN-3', 5'-NTA-3'and 5'-NGA-3' (N stands for generic nucleotide). Their role is still unknown, but since linear regression including these specific constellations showed a higher observable variance coverage than the model with only the basic descriptors, we may assume that solvent-analyte interactions are responsible for the exceptional behaviour of 5'-NAN-3' & 5'-ANN-3' trinucleotides and some intramolecular interactions of neighbouring nucleobases for 5'-TGN-3', 5'-NTA-3'and 5'-NGA-3' trinucleotides.

• MeSH
• adenin analogy a deriváty   izolace a purifikace   MeSH
• chromatografie s reverzní fází MeSH
• guanin analogy a deriváty   izolace a purifikace   MeSH
• kvantitativní vztahy mezi strukturou a aktivitou MeSH
• neuronové sítě MeSH
• oligonukleotidy izolace a purifikace   MeSH
• rozpouštědla MeSH
• simulace molekulární dynamiky MeSH
• statická elektřina MeSH
• thymin analogy a deriváty   izolace a purifikace   MeSH
• voda MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH

V skupine bázických esterov alkoxysubstituovanej kyseliny fenylkarbámovej sa využili umelé neurónové siete (ANN – artificial neural network) na predikciu HPLC retenčného faktora k. Veľmi dobré výsledky predikcie sa získali pre tri vyšetrované systémy: fenylová kolóna, mobilná fáza acetonitril/voda (retenčný faktor kPhAc), fenylová kolóna, mobilná fáza metanol/voda (retenčný faktor kPhMe) a C18 kolóna, mobilná fáza acetonitril/voda (retenčný faktor kC18Ac), ktoré sú vyjadrené závislosťami predikovaného retenčného faktora voči experimentálne nameranému. Úseky, ako aj smernice týchto zistených závislostí sa blížia k 0, resp. k 1. Výsledky pre systém C18 kolóna, mobilná fáza metanol/voda (retenčný faktor kC18Me) na predpoveď k neboli veľmi vhodné.

Artificial neural networks (ANN) were utilized to predict the HPLC retention factor k of a group of basic esters of alkoxyphenyl-substituted phenylcarbamic acid. Very good results were obtained in the prediction of three investigated systems: phenyl column, acetonitrile/water mobile phase (retention factor kPhAc), phenyl column, methanol/water mobile phase (retention factor kPhMe), and C18 column, acetonitrile/water mobile phase (retention factor kC18Ac), which are expressed by the dependences of the retention factor predicted vs. the retention factor experimentally measured. The intercepts and the slopes of the obtained dependences were close to 0 and 1, respectively. The results for the system C18 column, methanol/water mobile phase were not sufficiently suitable for the k prediction.

• MeSH
• anestetika lokální farmakokinetika   farmakologie   MeSH
• fenylkarbamáty farmakokinetika   farmakologie   izolace a purifikace   MeSH
• financování organizované MeSH
• kvantitativní vztahy mezi strukturou a aktivitou MeSH
• neuronové sítě MeSH
• teoretické modely MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH

• Klíčová slova
• elektroforéza kapilární,

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• fyzika, biofyzika
• biomedicínské inženýrství