scholarly journals Comparative Chiral Separation of Thalidomide Class of Drugs Using Polysaccharide-Type Stationary Phases with Emphasis on Elution Order and Hysteresis in Polar Organic Mode

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 111
Author(s):  
Mohammadhassan Foroughbakhshfasaei ◽  
Máté Dobó ◽  
Francisc Boda ◽  
Zoltán-István Szabó ◽  
Gergő Tóth
Keyword(s):  
Mobile Phase ◽  
Stationary Phases ◽  
Screening Strategy ◽  
Chiral Selector ◽  
Elution Order ◽  
Mobile Phases ◽  
Chiralcel Od ◽  
Separation Capacity ◽  
New Type ◽  
Chiral Screening

The enantioseparation of four phthalimide derivatives (thalidomide, pomalidomide, lenalidomide and apremilast) was investigated on five different polysaccharide-type stationary phases (Chiralpak AD, Chiralpak AS, Lux Amylose-2, Chiralcel OD and Chiralcel OJ-H) using neat methanol (MeOH), ethanol (EtOH), 1-propanol (PROP), 2-propanol (IPA) and acetonitrile (ACN) as polar organic mobile phases and also in combination. Along with the separation capacity of the applied systems, our study also focuses on the elution sequences, the effect of mobile phase mixtures and the hysteresis of retention and selectivity. Although on several cases extremely high resolutions (Rs > 10) were observed for certain compounds, among the tested conditions only Chiralcel OJ-H column with MeOH was successful for baseline-separation of all investigated drugs. Chiral selector- and mobile-phase-dependent reversals of elution order were observed. Reversal of elution order and hysteresis of retention and enantioselectivity were further investigated using different eluent mixtures on Chiralpak AD, Chiralcel OD and Lux Amylose-2 column. In an IPA/MeOH mixture, enantiomer elution-order reversal was observed depending on the eluent composition. Furthermore, in eluent mixtures, enantioselectivity depends on the direction from which the composition of the eluent is approached, regardless of the eluent pair used on amylose-based columns. Using a mixture of polar alcohols not only the selectivities but the enantiomer elution order can also be fine-tuned on Chiralpak AD column, which opens up the possibility of a new type of chiral screening strategy.

scholarly journals Estimation of Solute-Stationary Phase and Solute-Mobile Phase Interactions in the Presence of Ionic Liquids

Separations ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 40
Author(s):  
María José Ruiz-Ángel
Keyword(s):  
Ionic Liquids ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Retention Mechanism ◽  
Chromatographic Behavior ◽  
Chemical Equilibria ◽  
Suppression Effect ◽  
Mobile Phases

The presence of free silanols on alkyl-bonded reversed-phase stationary phases is responsible for broad and asymmetrical peaks when basic drugs are chromatographed with conventional octadecylsilane (C18) columns due to ionic interactions. In the last few years, ionic liquids (ILs) have attracted attention to reduce this undesirable silanol activity. ILs should be considered as dual modifiers (with a cationic and anionic character), which means that both cations and anions are able to adsorb on the stationary phase, creating a positively or negatively charged layer, depending on the relative adsorption. The accessibility of basic compounds to the silanols is prevented by both the IL cation and anion, improving the peak profiles. A comparative study of the performance of six imidazolium-based ILs, differing in their cation/anions, as modifiers of the chromatographic behavior of a group of ten β-adrenoceptor antagonists, is addressed. Mobile phases containing cationic amines (triethylamine and dimethyloctylamine) were used as a reference for the interpretation of the results. Using a mathematical model based on two chemical equilibria, the association constants between the solutes and modified stationary phase as well as those between solutes and the additive in the mobile phase were estimated. These values, together with the changes in retention and peak shape, were used to obtain conclusions about the retention mechanism, changes in the nature of the chromatographic system, and silanol suppression effect.

scholarly journals Overloading study of ionized compounds in hydrophilic interaction chromatography

Chemija ◽  
2018 ◽  
Vol 29 (4) ◽  
Author(s):  
Inga Baškirova ◽  
Vilma Olšauskaitė ◽  
Audrius Padarauskas
Keyword(s):  
Mobile Phase ◽  
Stationary Phases ◽  
Hydrophilic Interaction Chromatography ◽  
Ionic Interactions ◽  
Loading Capacity ◽  
Hydrophilic Interaction ◽  
Ph Values ◽  
Opposite Trend ◽  
Mobile Phases ◽  
Acidic Compounds

The overloading behaviour of charged acidic (acetylsalicylic acid and nicotinic acid) and basic (creatinine and 1-ethyl-2,3-dimethylimidazolium) solutes was investigated on two stationary phases (bare silica and amidebonded silica) in the hydrophilic interaction chromatography separation mode at three mobile phase pH values (3.0, 5.0 and 7.0). On the bare silica both cationic solutes showed the increased peak tailing as the sample load increased. However, on the amide phase they exhibited a quite different overloading behaviour. The peak shapes for creatinine showed the increased tailing whereas for 1-ethyl-2,3-dimethylimidazolium peak fronting occurs with the sample load. Anionic solutes on both phases showed the increased peak fronting as the sample load increased. In neutral and slightly acidic mobile phases the loadability of the bare silica phase was much higher for bases than for acids. In addition, the loading capacity for the bases increases with pH whereas an opposite trend was observed for the acidic compounds. The amide phase gave similar loading capacity values for both types of solutes and its loadability is less sensitive to pH changes, compared to that of bare silica. The obtained results indicate that ionic interactions with dissociated surface silanols play an important role in the overloading behaviour of charged solutes.

Syntéza a HPLC enantioseparácia nových derivátov 3-alkoxy-4-hydroxyfenylalkanónov typu potenciálnych α/β-blokátorov

2021 ◽  
Vol 70 (1) ◽  
pp. 51-58
Author(s):  
Čižmáriková Ružena ◽  
Habala Ladislav ◽  
Valentová Jindra ◽  
Šmátralová Dana
Keyword(s):  
Thin Layer ◽  
Mobile Phase ◽  
Nmr Spectra ◽  
Chiral Selector ◽  
Heterocyclic Amines ◽  
Selectivity Factor ◽  
Subsequent Reaction ◽  
Piperazine Derivatives ◽  
Mobile Phases ◽  
Layer Chromatography

The present paper reports the synthesis of a series of seven compounds with a hetero aminopropanol chain. The compounds were prepared by the conversion of 3-alkoxy-4-hydroxyphenyl alkanones with 2-chloromethyl oxirane and subsequent reaction of the products with heterocyclic amines (pyrrolidine, azepane, 4-methylpiperazine and 2-methoxyphenyl piperazine). The target compounds were synthesized in the form of racemates. The purity of the products was confirmed by thin layer chromatography and their IR, UV-VIS and 1H-NMR spectra were recorded. Enantioseparation of the racemic products was accomplished by HPLC on a Chiralpak AD chiral chromatographic column with tris(3,5-dimethylphenyl)carbamate as the chiral selector. The efficiency of enantioseparation was determined in relation to the composition of the mobile phase (hexane : ethanol : methanol : ethylethanamine) and to the structure of the prepared compounds. Baseline separation was achieved with all compounds using mobile phases A (78 : 11 : 11 : 0,1 v/v/v/v) and B (80 : 10 : 10 : 0,1 v/v/v/v), with selectivity factor ranging from 1.07 to 1.42 and resolution from 0.76 to 5.47. The mobile phase containing a higher amount of hexane did not allow for successful enantioseparation of the piperazine derivatives.

scholarly journals Computational study of the chromatographic enantioseparation of tris(acetylacetonato)cobalt(III) complexes on an arginine complex of cobalt(III) acting as a chiral selector

2002 ◽  
Vol 67 (11) ◽  
pp. 735-744 ◽  
Author(s):  
Ljiljana Cuckovic ◽  
Ismet Hodzic ◽  
Svetozar Niketic
Keyword(s):  
Total Energy ◽  
Chromatographic Separation ◽  
Predictive Power ◽  
Computational Study ◽  
Stationary Phases ◽  
Chiral Selector ◽  
Experimental Results ◽  
Elution Order ◽  
Practical Applications ◽  
Energy Of Interaction

Acomputational procedure for the modelling of chromatographic separation of neutral tris(acetylacetonato)cobalt(III) into enantiomers on a dinitrobis(arginine)cobalt(III) complex as a chiral selector is described. Predicted elution order calculated from the differences in total energy of interaction for ? and ? selectands is in agreement with the experimental results. Predictive power of the method and its possible practical applications in designing efficient chiral stationary phases is demonstrated.

Enantioseparation of 3α-acyloxy-6β-acetoxyltropane compounds with Chiralpak AD and Chiralcel OD-H chiral stationary phases

2015 ◽  
Vol 33 (6) ◽  
pp. 647
Author(s):  
Bin CHENG ◽  
Yifan XIE ◽  
Youmin HU ◽  
Huizhong LIU ◽  
Yinyao NIU ◽  
...  
Keyword(s):  
Stationary Phases ◽  
Chiral Stationary Phases ◽  
Chiralcel Od

scholarly journals Analysis of Some Biogenic Amines by Micellar Liquid Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Irena Malinowska ◽  
Katarzyna E. Stępnik
Keyword(s):  
Liquid Chromatography ◽  
Sodium Dodecyl Sulfate ◽  
Biogenic Amines ◽  
Physicochemical Parameters ◽  
Mobile Phase ◽  
Sodium Dodecyl ◽  
Micellar Liquid Chromatography ◽  
Ionic Surfactant ◽  
Mobile Phases ◽  
Dodecyl Sulfate

Micellar liquid chromatography (MLC) with the use of high performance liquid chromatography (HPLC) was used to determine some physicochemical parameters of six biogenic amines: adrenaline, dopamine, octopamine, histamine, 2-phenylethylamine, and tyramine. In this paper, an influence of surfactant’s concentration and pH of the micellar mobile phase on the retention of the tested substances was examined. To determine the influence of surfactant’s concentration on the retention of the tested amines, buffered solutions (at pH 7.4) of ionic surfactant—sodium dodecyl sulfate SDS (at different concentrations) with acetonitrile as an organic modifier (0.8/0.2 v/v) were used as the micellar mobile phases. To determine the influence of pH of the micellar mobile phase on the retention, mobile phases contained buffered solutions (at different pH values) of sodium dodecyl sulfate SDS (at 0.1 M) with acetonitrile (0.8/0.2 v/v). The inverse of value of retention factor () versus concentration of micelles () relationships were examined. Other physicochemical parameters of solutes such as an association constant analyte—micelle ()—and partition coefficient of analyte between stationary phase and water (hydrophobicity descriptor) () were determined by the use of Foley’s equation.

Sign in / Sign up

Export Citation Format

Share Document