Stationary Phase In Ion Chromatography Research Articles

The Novel Polymethacrylate Based Hydrophilic Stationary Phase for Ion Chromatography.

Ion chromatography is widely used as a useful and powerful tool for the analysis of anionic and cationic components found in waters and aqueous media. The performance and selectivity of ion chromatography are based on the stationary phase column packed material. In this study, it is aimed to develop new column material with quaternary ammonium functional group based on monodisperse polymeric particles for ion chromatography and to investigate their chromatographic performance. For the analysis of inorganic anions by ion chromatography, new stationary phases macroporous monodisperse particles based on 3-chloro-2-hydroxy propylmethacrylate-co-ethylene dimethacrylate are obtained as column packing material. 3-chloro-2-hydroxy propylmethacrylate and ethylene glycol dimethacrylate are transformed to porous monodisperse particle form by using glycidyl methacrylate as the seed latex and ethyl benzene as the porogen solvent via micro-suspension polymerization technique. Then macroporous monodisperse particles surface is functionalized by triethylamine so strong anion exchange is obtained for ion chromatography packing material. A series of stationary phases prepared from polymer particles containing different amounts of porogen solvent were tested. The results show that column packing material is successful to separate inorganic anions mixture such as F-, Cl-, NO2-, Br-, NO3- by using the carbonate and bicarbonate solutions as mobile phases.

Retention of inorganic anions using mesoporous zirconia spheres modified with anion-exchange groups as the stationary phase for ion chromatography.

A zirconia (ZrO2) stationary phase with a chemically fixed silane coupling agent (trimethyl [3-(trimethoxysilyl)propyl]ammonium chloride; TMA), which possesses quaternary ammonium functional groups, is evaluated as a separation column for ion chromatography (IC) of anions. The selectivity for anions varies depending on the amount of TMA immobilized on the ZrO2. The TMA-ZrO2, with an anion-exchange capacity of 17 ± 3µeq/g, shows an anion-exchange reaction that involves the specific retention of fluoride ion on ZrO2. The TMA-ZrO2 exhibits a decrease of the anion resolution with an increase of the eluent pH and an enhancement of the selective separation of fluorideion with an increase of the column temperature. Through this study, the TMA-ZrO2 stationary phase shows potential as a new medium for ion separation.

Silica gel functionalized with imidazolium group via click chemistry – new stationary phase for ion chromatography

This manuscript describes the preparation of a simple effective ion-exchange material based on silica gel, on the surface of which methylimidazolium bromide is fixed using a click reaction. The resulting material was used as a stationary phase for the separation and determination of Cl–, NO2–, NO3–, I–, and SO42– using ion exchange chromatography. The separation efficiency and retention factors for the selected anions were studied in the pH range 3.5–6.5. The proposed material was used for the determination of Cl–, SO42– in water and can be suggested for successful use in real water samples.

Preparation and characterization of graphitic carbon-nitride nanosheets agglomerated poly (styrene-divinylbenzene) anion-exchange stationary phase for ion chromatography

In this paper, graphitic carbon-nitride (g-C3N4) nanosheets agglomerated poly (styrene–divinylbenzene) (PS-DVB) anion-exchange stationary phase was prepared and applied in ion chromatography. The mono-dispersity, diameters, porosity and surface characteristics of g-C3N4 nanosheets agglomerated PS-DVB microspheres were measured by scanning electron microscope and nitrogen adsorption–desorption measurements. The quaternized g-C3N4 nanosheets agglomerated PS-DVB anion-exchange stationary phase was characterized by Fourier Transform Infrared Spectroscopy, Elemental Analysis, Breakthrough Curve and Mechanical Intensity Test. The chromatographic properties of self-fabricated anion-exchange column packed with septuple quaternized g-C3N4 nanosheets agglomerated PS-DVB microspheres were investigated by separating six conventional anions and four monovalent organic acids. According to the results, g-C3N4 nanosheets were successfully agglomerated onto the surface of PS-DVB microspheres; g-C3N4 nanosheets agglomerated PS-DVB showed good reactivity due to the presence of terminal amino groups; baseline separation of six conventional anions and four monovalent organic acids were obtained on this column. Finally, the self-fabricated column was successfully applied to the determination of mercaptoacetic acid in water reducer.

Poly(ethylene glycol) Methyl Ether Methacrylate-bonded Stationary Phase in Ion Chromatography and Its Application to Seawater Samples.

A fast and simple ion chromatographic method for the determination of iodide in seawater is reported using poly(ethylene glycol) methyl ether methacrylate-bonded stationary phase. Poly(ethylene glycol) methyl ether methacrylate was reacted with primary amino groups of aminopropylsilica in N,N-dimethylformamide at 80°C. The prepared stationary phases were evaluated by analyzing several inorganic anions and the retention behavior was observed. Various chromatographic parameters were optimized for the separation of these anions. Although there were no ion-exchange sites on the resulted stationary phases, the results obtained suggested that an ion-exchange mechanism was involved in the retention of analyte anions. With 0.15 μL injection, the limit of quantitation of iodide was 26 μg L-1 when 200 mM NaCl was selected as the eluent. This stationary phase was applied to the analysis of direct and fast determination of iodide in real seawater samples successfully with the recovery rates of 98.1 and 104.9%.

A Criterion of Selection of Stationary Phases for Improving the Performance of Chromatographic Analysis

A convenient criterion is derived for the characterization of chromatographic stationary phases capable of providing an efficient and rapid analysis of a given class of mixtures based on a theoretical analysis of the dependence of specific efficiency on capacity. The criterion implicitly contains information about the internal structure of the column packing grain. The derivation of an expression for the criterion is accompanied by a theoretical substantiation of the interval for the working grain size of the column packing, which has a capacity and represents the region of particle diffusion. It is shown that the ratios are universal regardless of the type of the chromatographic process. A new characteristic of the quality of column packing can be called its performance factor, which shows the ratio of the actual to the maximum performance of the chromatographic system with a given selectivity. Examples of determining the quality criterion of a stationary phase for ion chromatography are given.

Covalent hyperbranched porous carbon nanospheres as a polymeric stationary phase for ion chromatography.

This work presents a method for covalent quaternization of porous carbon nanospheres (PCNSs) and their application as anion exchanging stationary phase for ion chromatography. The PCNSs were covalently quaternized via the dehydration condensation between surface carboxyl groups and polyethyleneimine. This was followed by a repeated epoxy-amine addition reaction with ethylene glycol diglycidyl ether. As a result, surface methylamino groups are formed. The electrostatic interaction between quaternized PCNSs and sulfonated poly(polystyrene-co-divinylbenzene) resulted in the formation of an agglomerated stationary phase. The capacities (41.5-90.2 μequiv) and pressures (540-1150psi) of column packed with novel phases (100 × 4.0mm i.d.) were further increased with grafted polymer layer counts (2-5). Common inorganic anions, small organic acids and saccharides were rapidly separated on the new phases. The column efficiencies for seven inorganic anions ranged from 38,400 to 13,200 plates m-1. Through 8days of flushing test, the RSD values for retention time and efficiencies varied from 0.56% to 1.32%, and from 0.34% to 0.74%, respectively. Graphical abstract Schematic presentation of the covalent modification of porous carbon nanospheres (PCNSs) with hyperbranched quaternized polymers via the amidation and epoxy-amine addition reaction was depicted. Functionalized PCNSs were further applied as agglomerated materials of polymeric stationary phase for ion chromatography (IC).

Novel Stationary Phases for Ion Chromatography and Hydrophilic Interaction Liquid Chromatography

The review covers the research of the Laboratory of Chromatography of the Division of Analytical Chemistry of the Department of Chemistry of Moscow State University in the development of new stationary phases for hydrophilic interaction liquid chromatography and ion chromatography performed in 2007–2017. The principles that guided the team in selecting matrices for each type of adsorbents, approaches to the modification of surface, and the methods of forming functional layers are discussed. The revealed regularities of changes in the chromatographic properties of materials on varying the structural fragments of the functional layers are described in detail, which enabled the authors to develop approaches to obtaining stationary phases that are not inferior to commercial analogs in efficiency and selectivity.

Investigation of Chromatographic Performance of Hyperbranched Amine-Modified Stationary Phases in Ion Chromatography

Investigation of Chromatographic Performance of Hyperbranched Amine-Modified Stationary Phases in Ion Chromatography

Hydrothermal carbonaceous sphere based stationary phase for anion exchange chromatography

Monodisperse carbonaceous spheres produced by the hydrothermal carbonization of sucrose were first applied as green stationary phase for ion chromatography after quaternization. Depending on the polycondensation of methylamine and 1,4-butanediol diglycidyl ether, polymer containing quaternary ammonium groups were facilely grafted onto the surfaces of hydrothermal carbonaceous spheres (HCSs). The quaternized HCSs with different number of polyelectrolyte layers were characterized by scanning electron microscopy, brunauer-emmett-teller, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and elemental analysis. The measurements of breakthrough curves demonstrated that more layers of grafted polyelectrolyte resulted in higher anion exchange capacity of stationary phase. With good stability, common inorganic anions, monocarboxylic acids, polarizable anions and carbohydrates were effectively separated on the stationary phases, respectively. The high hydrophilicity of HCS surface afforded excellent peak symmetry for all analytes. Furthermore, high-capacity HCSs stationary phase was successfully applied to detect fluoride in tea samples.

Hydrothermal carbon nanosphere-based agglomerated anion exchanger for ion chromatography

This work reports the application of hydrothermal carbon nanospheres (HCNSs) as stationary phases in ion chromatography. HCNSs were facilely quaternized through polycondensation of methylamine and 1,4-butanediol diglycidyl ether. The quaternization was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Owing to the electrostatic interaction, quaternized HCNSs were equably attached onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to construct the anion exchangers. The aggregation was verified by scanning electron microscopy and elemental analysis. Common anions, aliphatic monocarboxylic acids, polarizable anions, and aromatic acids were well separated on the stationary phases with good stability and symmetry. The prepared column was further applied to detect phosphate content in Cola drink samples. The limit of detection (S/N=3) was 0.09mg/L, and the relative standard deviation (n=10) of retention time was 0.31%. The average recovery was 99.58%.

Separation of uremic toxins from urine with resorcinarene-based ion chromatography columns

People with chronic kidney disease suffer from uremic toxins which accumulate in their bodies. Detection and quantification of uremic toxins help diagnose kidney problems and start patient care. The aim of this research was to seek a new method to assist this diagnosis by trace level detection and separation of guanidine containing uremic toxins in water and urine. To detect and quantify the uremic toxins, new stationary phases for ion chromatography (IC) columns based on glutamic acid functionalized resorcinarenes bound to divinylbenzene macroporous resin were prepared. The new column packing material afforded separation of the five compounds: guanidinoacetic acid, guanidine, methylguanidine, creatinine, and guanidinobenzoic acid in 30min. Peak resolutions ranged from 7.6 to 1.3. Gradient elutions at ambient temperature with methanesulfonic acid (MSA) solution as eluent resulted in detection levels in water from 10 to 47ppb and in synthetic urine from 28 to 180ppb. Limits of quantification for the analytes using pulsed amperometric detection were 30–160ppb in water and 93–590ppb in urine. Trace levels of creatinine (1ppm) were detected in the urine of a healthy individual using the columns.

Preparation and characterization of a latex-agglomerated anion exchange chromatographic stationary phase

Allyl glycidyl ether (AGE) was selected as the copolymerization monomer to prepare a copolymer latex-agglomerated anion exchange chromatography stationary phase for ion chromatography (IC). First, allyl glycidyl ether-styrene (AGE-ST) copolymer latex was prepared by the saponification emulsion polymerization method. It was then quaternized by reacting alternatively with methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDGE) and agglomerated on the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) microspheres to obtain a copolymer latex-agglomerated anion exchange chromatography stationary phase. The stationary phase was characterized by scanning electron microscopy (SEM), FT-IR and elemental analysis (EA). It was found that the diameters of the PS-DVB microsphere and AGE-ST copolymer latex were about 6 μm and 300 nm, respectively. The quaternized AGE-ST copolymer latex was successfully agglomerated on the surface of PS-DVB microspheres and the nitrogen content increased as quaternization time was increased. The chromatographic properties were evaluated by separating conventional anions and organic acids. The results showed that the quaternized AGE-ST copolymer latex-agglomerated PS-DVB anion exchange column exhibited good separation properties toward anions. Therefore, based on the good pH toleration and reaction activity of the newly developed stationary phase, it was concluded that using AGE as a monomer was a good choice.

Polyoxyethylene as the Stationary Phase in Ion Chromatography

The present article reviews the use of polyethylene glycol (PEG) or polyoxyethylene (POE) as the stationary phase for the separation of inorganic anions in ion chromatography and discusses about the retention mechanisms involved in the separation of anions on the novel stationary phases. PEG permanently coated on a hydrophobic stationary phase retained anions in the partition mode and allowed us to use high-concentration eluents because the retention of anions increased with increasing eluent concentration for most of the eluents. This situation was convenient to determine trace anions contained in seawater samples without any disturbance due to matrices. Chemically bonded POE stationary phases retained not only anions but also cations. Anions were retained in the ion-exchange mode, although POE chains possess no ion exchange sites. The retention behavior suggested that eluent cations could be trapped among multiple POE chains via ion-dipole interaction, and that the trapped cations worked as the anion-exchange sites. Anions could be separated using crown ether, i.e., cyclic POE, as the eluent additive with a hydrophobic stationary phase, where analyte anions were retained via electrostatic interaction with the eluent cation trapped on the crown ether.

Silica based click amino stationary phase for ion chromatography and hydrophilic interaction liquid chromatography

A silica based amino stationary phase was prepared by immobilization of propargylamine on azide-silica via click chemistry. This readily prepared click amino stationary phase demonstrated good selectivity in separation of common inorganic anions under ion chromatography (IC) mode, and the triazole ring in combination with free amino group was observed to play a major role for separation of the anions examined. On the other hand, the stationary phase also showed good hydrophilic interaction liquid chromatography (HILIC) properties in the separation of polar compounds including nucleosides, organic acids and bases. The retention mechanism was found to match well the typical HILIC retention.

Separation of inorganic anions on hydrophobic stationary phases in ion chromatography

Inorganic anions were separated on hydrophobic stationary phases such as triacontyl-functionalized silica. Eluent conditions were examined in detail, and iodate, nitrate, iodide, and thiocyanate could be separated by using aqueous solutions. The effect of the eluent concentration on the retention of analyte anions was examined for a wide range of sodium sulfate concentrations of up to 1 M. The retention factor of hydrophobic anions decreased with increasing sodium sulfate concentration in the lower concentration region, while it increased with increasing sodium sulfate concentration in the higher concentration region. The addition of a small amount of an organic substance such as acetonitrile and tetraethylene glycol increased the retention of iodide and thiocyanate, while the addition of alcohols decreased their retention. Operating at lower temperature also increased the retention of analyte anions. It was expected that inorganic anions were retained on the stationary phase via hydrophobic interactions. The retention mechanism was discussed, considering the results obtained.

Functionalized polymeric stationary phases for ion chromatography

Synthesis and properties of the multilayered stationary phases, which contain quaternary amine functional groups for the analysis of anions by ion chromatography, are described. The bonded phases were characterized by elemental analysis, solid-state (13)C NMR spectroscopy and chromatographic methods. The surface of 1,4-di(2-hydroxy-3-methacryloyloxypropoxy)phenol (solid support) was coated with polymeric layers formed by condensation polymerization of primary amine with diepoxide. Each layer of the anion exchange stationary phase consists of copolymer of methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDE). A series of stationary phases with different numbers of polymerized layers were tested. The separation of an inorganic anions sample (F(-), Cl(-), NO(2)(-), Br(-), NO(3)(-), additionally HPO(4)(2-) and SO(4)(2-)) was performed. In the measurement, a hydroxide, carbonate, bicarbonate and their mixture were used as mobile phases.

Ion chromatography on carbon clad zirconia modified by diazonium chemistry and functionalized latex particles

This work explores the potential of 3 μm carbon coated zirconia particles as a stationary phase for ion chromatography for the separation of organic acids and inorganic ions. A 4-phenylsulfonic acid functionality is introduced onto the carbon surface by reducing 4-phenylsulfonic acid diazonium chloride with borohydride in the presence of carbon clad zirconia particles. The elemental sulfur analysis gave 132 μeq-SO(3)H/g carbon clad zirconia and 2% S atomic concentration by XPS analysis. The -SO(3)(-) groups serve as electrostatic anchors for latex nanoparticles bearing quaternary triethylamine functional groups. The agglomeration step in 5 × 0.4 cm i.d. columns converts the packed particles into an anion exchanger. The breakthrough curves with nitrate indicate a capacity of 3 μeq/column. Separation of common organic acids and inorganic ions using carbonate eluent and suppressed conductivity detection yield plate heights (H) of 0.023-0.05 mm.

Separation of Inorganic Anions on a Pyridine Stationary Phase in Ion Chromatography

The retention behavior of inorganic anions on a pyridine stationary phase commercially available for hydrophilic interaction chromatography was examined in ion chromatography. Inorganic anions were retained on a protonated pyridine stationary phase under acidic eluent conditions (pH 3.1-3.3) in the ion-exchange mode. The logarithm of the retention factor of analytes was linear to the logarithm of the eluent concentration, and the slopes of the plots were -0.55 to -0.64, except for nitrite (-0.39). The smaller slope for nitrite was due to the fact that nitrous acid is weak (pK(a) 3.25 at 25 degrees C) and was partially ionized under the operating conditions. The elution order of the examined anions was the same as that observed in common ion chromatography. The present system was applied to the determination of UV-absorbing anions contained in saliva.

Poly(ethylene oxide)-bonded stationary phase for capillary ion chromatography

Methyl-capped poly(ethylene oxide) moieties were chemically bonded to silica gel using an amine-reactive modification reagent and evaluated as the stationary phase for ion chromatography. In this work, primary amino groups of an aminopropylsilica packing material were reacted with methyl-PEO(12)-NHS ester (succinimidyl-{[N-methyl]-dodecaethyleneglycol} ester) in phosphate buffer (pH 7.0) at room temperature. The prepared poly(ethylene oxide)-bonded stationary was evaluated for the separation of inorganic anions, and the retention behavior of inorganic anions on the prepared stationary phase was examined. The elution order of the investigated anions was the same as that observed in common ion chromatography. Both cations and anions of the eluent affected the retention of the analyte anions. Ion exchange was involved for the retention of analyte anions, although the present stationary phase does not possess any discrete ion-exchange sites. The stationary phase was applied to the separation of trace anions contained in tap water and a rock salt.