scholarly journals Evaluating Relative Retention of Polar Stationary Phases in Hydrophilic Interaction Chromatography

Separations ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 42 ◽  
Author(s):  
Guo ◽  
Bhalodia ◽  
Fattal
Keyword(s):  
Mobile Phase ◽  
Stationary Phases ◽  
Hydrophilic Interaction Chromatography ◽  
Retention Data ◽  
Hydrophilic Interaction ◽  
Model Compounds ◽  
Testing Procedures ◽  
Relative Retention ◽  
Wide Range ◽  
The Right

A large number of polar stationary phases with diverse chemistry have been developed for various applications in hydrophilic interaction chromatography (HILIC). However, column manufacturers employ different testing procedures to evaluate retention of the polar stationary phases. This renders the retention data impossible for comparison and makes it difficult for the users to select the right stationary phase based on retention. We have evaluated 25 polar stationary phases using cytosine and uracil as the model compounds in various mobile phase conditions. These stationary phases show a wide range of retention characteristics for the model compounds. The ranking of the stationary phases does not change drastically with the acetonitrile level in the mobile phase.

scholarly journals Evaluating the Adsorbed Water Layer on Polar Stationary Phases for Hydrophilic Interaction Chromatography (HILIC)

Separations ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 19 ◽  
Author(s):  
Yong Guo ◽  
Nidhi Bhalodia ◽  
Bassel Fattal ◽  
Ioannis Serris
Keyword(s):  
Mobile Phase ◽  
Stationary Phases ◽  
Volume Ratio ◽  
Water Layer ◽  
Adsorbed Water ◽  
Polar Compounds ◽  
Hydrophilic Interaction Chromatography ◽  
Hydrophilic Interaction ◽  
Column Temperature ◽  
Wide Range

The water-rich liquid layer immobilized on the surface of the polar stationary phases is critical to the retention of polar compounds in hydrophilic interaction chromatography (HILIC). Although the presence of the adsorbed water layer has been investigated and confirmed by multiple techniques, there is a lack of quantitative measures that can be easily determined and linked to chromatographic parameters. This study proposes a simple measure termed volume ratio (the ratio of the adsorbed water layer volume and the mobile phase volume) that can be easily determined using toluene elution volume. The volume ratio values measured using the proposed method indicate that the volume of the adsorbed water layer varies in a wide range in the stationary phases commonly used in HILIC separation. It was observed that the volume ratio increases with the acetonitrile content and ammonium acetate concentration in the mobile phase. In addition, increasing the column temperature had the effect of reducing the volume ratio and diminishing the adsorbed water layer.

scholarly journals Evaluating the Adsorbed Water Layer on Polar Stationary Phases for Hydrophilic Interaction Chromatography (HILIC)

2019 ◽  
Author(s):  
Yong Guo ◽  
Nidhi Bhalodia ◽  
Bassel Fattal ◽  
Ioannis Serris
Keyword(s):  
Mobile Phase ◽  
Stationary Phases ◽  
Volume Ratio ◽  
Quantitative Measure ◽  
Water Layer ◽  
Adsorbed Water ◽  
Quantitative Information ◽  
Hydrophilic Interaction Chromatography ◽  
Hydrophilic Interaction ◽  
Column Temperature

The water-rich liquid layer immobilized on the surface of the polar stationary phases is critical to the retention of polar compounds in hydrophilic interaction chromatography (HILIC). Although the presence of the adsorbed water layer has been investigated and confirmed by multiple techniques, there is a lack of quantitative measure that can be easily determined and linked to chromatographic parameters. This study proposes a simple measure termed volume ratio (the ratio of the adsorbed water layer volume and the mobile phase volume) that provides a relative, but quantitative information on the adsorbed water layer and may be linked to the phase ratio. The volume ratio can be easily determined using toluene elution volume. The volume ratio values are measured in 25 polar stationary phases in various mobile phase conditions. In addition to the acetonitrile content in the mobile phase, ammonium acetate concentration in the mobile phase and column temperature also have significant influences on the volume ratio and the adsorbed water layer.

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.

scholarly journals A Study of Retention Behavior and Method Development of Salbutamol Sulfate in Hydrophilic Interaction Chromatography

2020 ◽  
Vol 10 (03) ◽  
pp. 344-348
Author(s):  
Ashraf Saad Rasheed ◽  
Ali Saad Ali
Keyword(s):  
Mobile Phase ◽  
Method Development ◽  
Stationary Phases ◽  
Hydrophilic Interaction Chromatography ◽  
Retention Behavior ◽  
Salbutamol Sulfate ◽  
Hydrophilic Interaction ◽  
Large Capacity ◽  
Calibration Curves

For chromatographical separation and estimation of salbutamol sulfate, zwitterionic stationary phases with large capacity were obtained by zwitter-molecules attached to a polystyrene-divinylbenzene (PS/DVB) particle. Salbutamol sulfate retention activity was studied with eluent at various pH mobile phase, mobile phase concentrations, and acetonitrile (ACN) percentage. The methods of separation are based on separating the salbutamol sulfate into hydrophobic and cations interactions. Linearity of 0.01 to 0.9 μg.mL-1 for two columns was developed with direct calibration curves, %RSD percent (0.48 ± 0.12 and 0.49 ± 0.22), LoD (0.058 and 0.04 μg.mL-1), and LoQ (0.203 and 0.14 μg.mL-1) were created, respectively.

scholarly journals Gradient HPLC in the determination of drug lipophilicity and acidity

2001 ◽  
Vol 73 (9) ◽  
pp. 1465-1475 ◽  
Author(s):  
Roman Kaliszan ◽  
Piotr Haber ◽  
Tomasz Baczek ◽  
Danuta Siluk
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Standard Procedure ◽  
Gradient Elution ◽  
Log P ◽  
Retention Data ◽  
Organic Modifier ◽  
Wide Range ◽  
Aqueous Component ◽  
Initial Ph

The linear-solvent strength (LSS) model of gradient elution in high-performance liquid chromatography (HPLC) has been demonstrated to provide parameters of lipophilicity and acidity of analytes. pKa and log kw values are determined in three gradient runs. The first two experiments use an aqueous buffered eluent with a wide-range organic modifier gradient at pH of buffer, providing suppression of ionization of the analyte. That experiment allows an estimate of contents of the organic modifier in the mobile phase (%B), producing requested retention coefficient, k, for the nonionized form of the analyte. The next experiment is carried out with the latter %B and a pH-gradient of the aqueous component of the eluent that is sufficient to overlap possible pKa value of the analyte. The initial pH of the buffer used to make the mobile phase is selected to insure that the analyte is in nonionized form. The resulting retention time allows an estimate of pKa in a solvent of the given %B.The log kw parameter obtained correlated well with the corresponding value obtained by the standard procedure of extrapolation of retention data determined in a series of isocratic measurements. The correlation between log kw and the reference parameter of lipophilicity, log P, was very good for a series of test analytes. The values of pKa were found to correlate with the literature pKa data determined in water for a set of aniline derivatives studied.

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