L-Cysteine-Bonded Polymeric Monolithic Stationary Phase for Enantioseparation of Dansyl Amino Acids in Capillary Liquid Chromatography.

A chiral monolith stationary phase was fabricated by modifying the monolith surface using L-cysteine through a thiol-epoxy click reaction. L-cysteine-bonded polymer monolith was characterized by scanning electron microscopy/energy-dispersive X-ray and attenuated total reflectance Fourier-transformed infrared. The monomer content and modification temperature were carefully optimized to create a polymer monolith with excellent mechanical stability and permeability.

One-pot alkanolamines-assisted synthesis of magnetic mesoporous silica for synthetic dye adsorption.

Magnetic mesoporous silica (MMS) was synthesized in a one-pot system using various alkanolamines (triethanolamine, diethanolamine, tris (hydroxymethyl)aminomethane) as a basic catalyst. The characterization of the composites was conducted using scanning electron microscope, transmission electron microscope, X-ray diffractometer, surface area analyzer, and X-ray photoelectros spectroscopy. The MMS synthesized with tris(hydroxymethyl)aminomethane (MMS) showed the highest specific surface area, pore volume, and average pore diameter.

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.

Separation of Inorganic Anions Using an 18-Crown-6-ether-modified Organic Polymer Monolithic Stationary Phase in Capillary Ion Chromatography.

In this study, a monolithic organic polymer stationary phase was modified using 18-crown-6-ether for use in capillary ion chromatography. Its use in the separation of inorganic anions was investigated. The monolithic stationary phase was obtained by chemically bonding 2-aminomethyl-18-crown-6-ether to a polymer skeleton comprising glycidyl methacrylate and ethylene glycol dimethacrylate.

Optimization and Investigation of Zwitterionic Monolithic Stationary Phases for Capillary Ion Chromatography.

Zwitterionic monolithic columns were synthesized by a one-pot reaction using [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, ethylene dimethacrylate, methanol and 2,2'-azobis(isobutyronitrile) as the monomer, cross-linker, porogen and initiator, respectively. The optimum conditions for polymerization and the efficiency of the prepared columns were examined for ion chromatography. The separation of five kinds of inorganic anions was achieved.

Retention Behavior of Inorganic Anions in Hydrophilic Interaction Chromatography.

The retention behavior of inorganic anions was studied in hydrophilic interaction chromatography (HILIC). In this study, five kinds of HILIC stationary phases (amino, imidazole, amide, pyridine and zwitterionic) were investigated. It was found that only amino and imidazole columns exhibited the separation of inorganic anions under HILIC conditions.

Preparation of a hybrid monolithic stationary phase with allylsulfonate for the rapid and simultaneous separation of cations in capillary ion chromatography.

A hybrid monolithic column with sulfonate functionality was successfully prepared for the simultaneous separation of common inorganic cations in ion-exchange chromatographic mode through a simple and easy single-step preparation method. The strong cation-exchange moieties were provided directly from allylsulfonate, which worked as an organic monomer in the single-step reaction. Inorganic cations (Li(+), Na(+), K(+), NH4(+), Cs(+), Rb(+), Mg(2+), Ca(2+), and Sr(2+)) were separated satisfactorily by using CuSO4 as the eluent with indirect UV detection.

Polymer monolithic methacrylate base modified with tosylated-polyethylene glycol monomethyl ether as a stationary phase for capillary liquid chromatography.

A polyethylene glycol (PEG) monolithic column was successfully prepared in situ for the separation of inorganic anions in ion exchange capillary chromatography. By attaching PEG-groups into the methacrylate-based polymer, the number of theoretical plates was improved from 1433 to 3346 plates/m (when nitrate was used as the analyte). The retention behavior of iodate, bromate, nitrite, bromide and nitrate was observed under various salt aqueous solutions.

Evaluation of column hardware on liquid chromatography-mass spectrometry of phosphorylated compounds.

The influences of column hardware, such as chromatographic tubes and frits, on liquid chromatography-mass spectrometry (LC-MS) analysis of phosphorylated compounds were evaluated. The signal to noise ratio (S/N) and the intensity of flavin adenine dinucleotide (FAD) using a glass lined tube and polyethylene frit (GL-PE) column was approximately 170 and 90 times higher, respectively, than those using conventional stainless steel tube and stainless steel frit (S-S) column. In addition, the retention time of FAD using GL-PE column was the shortest compared to other columns.

Evaluation of column carryover of phosphorylated peptides and fumonisins by duplicated solvent gradient method in liquid chromatography/tandem mass spectrometry.

Columns made of three different materials were evaluated with regard to the carryover of phosphorylated peptides and fumonisins in liquid chromatography/tandem mass spectrometry (LC/MS/MS). In order to eliminate carryover caused by the injection operation in the autosampler, the column carryover was calculated using the duplicated solvent gradient method. A column made of a glass-lined stainless-steel tube and polyethylene frits (GL-PE column) yielded the most significant improvements in the peak shape and the carryover as compared to the other columns.

Capillary liquid chromatographic fingerprint used for discrimination of Zingiber montanum from related species.

Fingerprint analysis using capillary liquid chromatography (CLC) has been developed for discrimination of Zingiber montanum (ZM) from related species, for example Z. americans (ZA) and Z. zerumbet (ZZ).

Methacrylate-based diol monolithic stationary phase for the separation of polar and non-polar compounds in capillary liquid chromatography.

A monolithic capillary column prepared with glycidyl methacrylate (GMA) and poly(ethylene glycol) dimethacrylate (PEGDMA) was investigated and used in capillary liquid chromatography. The polymer monolith was synthesized in the presence of methanol and decanol as the biporogenic solvents by in situ polymerization of GMA and PEGDMA, and the optimum composition of monomer and porogen was investigated. After polymerization, glycidyl groups were hydrolyzed with sulfuric acid to produce diol groups at the surface of the porous monolith via epoxy-ring-opening.

Poly(ethylene oxide)-bonded stationary phase for separation of inorganic anions in capillary ion chromatography.

A tosylated-poly(ethylene oxide) (PEO) reagent was reacted with primary amino groups of an aminopropylsilica packing material (TSKgel NH2-60) in acetonitrile to form PEO-bonded stationary phase. The reaction was a single and simple step reaction. The prepared stationary phase was able to separate inorganic anions.

Separation of inorganic anions on a chemically bonded 18-crown-6 ether stationary phase in capillary ion chromatography.

Inorganic anions were separated on a chemically bonded 18-crown-6 ether (18C6E) stationary phase in capillary ion chromatography. In this study 18C6E groups were chemically bonded on silica gel via reaction with 3-glycidyloxypropyltrimethoxysilane, followed by reaction with 2-aminomethyl-18C6E. Analyte anions were separated in the ion-exchange mode based on the fact that the eluent cation was trapped on the 18C6E and it worked as the anion-exchange site.

Determination of iodide in seawater by capillary ion chromatography using hexadimethrine bromide modified C30 stationary phases.

A novel and simple capillary ion chromatographic method for the determination of iodide is reported. Separation was achieved on a laboratory-made packed capillary column (100 mm × 0.32 mm i.

Simultaneous determination of gingerols and shogaol using capillary liquid chromatography and its application in discrimination of three ginger varieties from Indonesia.

A new method using reversed phase capillary liquid chromatography was developed for simultaneous determination of four bioactive compounds found in ginger (Zingiber officinale) namely, 6-, 8-, 10-gingerol, and 6-shogaol. The separation of these four compounds was performed using C30 as the stationary phase and 60% acetonitrile as the mobile phase in isocratic elution mode with a flow rate of 5 μL/min. All four compounds were separated within 25 min with good resolution.

Simultaneous determination of inorganic cations by capillary ion chromatography with a non-suppressed contactless conductivity detector.

A non-suppressed capillary ion chromatographic method with a laboratory-made packed cation-exchange column (100 mm × 0.32 mm i.d.

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.

Separation of gold nanoparticles with a monolithic silica capillary column in liquid chromatography.

A separation system for gold nanoparticles was developed using monolithic silica capillary columns with 50 µm i.d., which were prepared via in-situ sol-gel processes.

Vitamin U-bonded stationary phase in capillary ion chromatography.

A vitamin U-bonded stationary phase was prepared and the retention behavior of inorganic anions was examined using ion chromatography. Inorganic anions were retained on the vitamin U-bonded stationary phase under acidic as well as neutral eluent conditions in the ion-exchange mode. The elution order of the examined anions under neutral eluent conditions was nearly the same as that observed in common ion exchange mode, while the elution order observed under acidic eluent conditions was completely different from that observed in common ion exchange mode.

Separation of inorganic anions by liquid chromatography with crown ether as eluent additive.

Inorganic anions were separated on a reversed-phase stationary phase dynamically modified with crown ether as a selector in capillary ion chromatography. The eluent contained crown ether, acetonitrile and a salt. Free and cation-trapped crown ether molecules in the eluent were adsorbed on a hydrophobic stationary phase such as triacontyl-functionalized silica (C30).

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.

Size separation of colloidally dispersed nanoparticles using a monolithic capillary column.

We developed a method to separate colloidally dispersed nanoparticles on monolithic capillary columns. Silica nanoparticles were eluted according to their sizes, and the plots of the logarithm of the size of nanoparticles against their elution volume showed good linearity (r=0.992) over wide range of sizes.

Simultaneous determination of antidepressants by non-aqueous capillary electrophoresis-time of flight mass spectrometry.

Simultaneous determination of 20 antidepressants in plasma samples was carried out by non-aqueous capillary electrophoresis with time of flight mass spectrometry via electrospray ionization, where a mixture of 60 mM ammonium acetate and 1M acetic acid in acetonitrile, and water, as well as methanol (100:1:0.5, v/v/v) was selected as the background electrolyte. By using time of flight mass spectrometry, accurate mass information was obtained and the background noise was dramatically decreased, thus causing a great improvement in qualitative ability.

Multifunctional separation mechanism on poly(oxyethylene) stationary phases in capillary liquid chromatography.

The retention behavior on poly(oxyethylene) (POE) chemically-bonded stationary phases was investigated in ion-exchange, reversed-phase (RP) and hydrophilic interaction (HILIC) modes in capillary liquid chromatography. The eluent cations fixed on the oxygen atoms of the POE chains by ion-dipole interaction worked as the anion-exchange sites for the separation of inorganic anions. Nonpolar analytes were retained on the POE stationary phases in the RP mode, while polar organic analytes were retained in the HILIC mode.