Recent progress in carbohydrate separation by high-performance liquid chromatography based on hydrophilic interaction

A lysine and amide functionalized polymer-based polar stationary phase for hydrophilic interaction chromatography

A novel polymer-based polar stationary phase for hydrophilic interaction chromatography (HILIC) is described. It was obtained by grafting lysine and acrylamide onto poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microspheres via ring-opening reaction of epoxy groups and free radical polymerization with pendant double bonds of the microspheres. Multiple types of polar groups including zwitterionic (carboxylate and amine), amide and diol onto the microspheres make them highly hydrophilic. It showed typical HILIC character and good separation performance towards model polar analytes. Negligible bleed level under gradient elution mode (up to 50% fraction of water) was observed. It also exhibited specific separation selectivity to ionic analytes and simultaneous separation of anions and cations could be achieved in ideal electrostatic selectivity elution order, e.g. I-< NO3- Collapse

Key Words

• Bleed
• Glycidyl methacrylate
• Hydrophilic interaction chromatography
• Polymer
• Zwitterionic stationary phase

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MESH Headings

• Amides
• Lysine
• Acrylamide
• Amines
• Chromatography

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Grants Collapse

Affiliation(s)

Ziteng Yu Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
Zongying Li Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
Feifang Zhang Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
Bingcheng Yang Engineering Research Center of Pharmaceutical Process Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.

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Chemical conjugation to differentiate monosaccharides by Raman and surface enhanced Raman spectroscopy

Sugars play important roles in numerous biological processes, from providing energy to modifying proteins to alter their function. Glycosylation, the attachment of a sugar residue to a protein, is the most common post translational modification. Identifying the glycans on a protein is a useful tool both for pharmaceutical development as well as probing the proteome and glycome further. Sugars, however, are difficult analytes to probe due to their isomeric nature. In this work, Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are used to identify different monosaccharide species based on the vibrational modes of these isomeric analytes. The weak scattering of the sugars was overcome through conjugation with phenylboronic acid to provide a larger Raman scattering cross section and induce slight changes in the observed spectra associated with the structure of the monosaccharides. Spontaneous Raman, SERS in flow, and static SERS detection were performed in order to discriminate between arabinose, fructose, galactose, glucose, mannose, and ribose, as well as provide a method for identification and quantification for these sugar conjugates.

Retention behaviors of pre-column derivatized mono-, di- and oligosaccharides in various modes of high performance liquid chromatography

Three LC-based methods, including reversed-phase chromatography (RPC), ion-pair RPC and weak anion-exchange chromatography (WAX), were examined in the separations of precolumn derivatized mono- and oligosaccharides with the following three tagging agents: 1-naphthylamine (1-NA), 2-aminoanthracene (2-AA), and 3-amino-2,7-naphthalenedisulfonic acid (ANDSA). Due to differences in their charges and polarity, the three tagging agents imparted the sugar derivatives varying elution patterns in the three, just mentioned, chromatographic modes. While RPC yielded high resolution separations for 1-NA- and 2-AA-sugar derivatives, ion-pair RPC in the presence of the ion-pairing agent dodecyl trimethylammonium bromide (DTAB) in the mobile phase exhibited far more resolution and selectivity than WAX in the separation of ANDSA-sugar derivatives. This finding portrays the fact that an octadecyl column operating in ion-pair RPC mode can eliminate in most cases the need for an ion-exchange column for bioanalytical separations of ionic or ionizable species. Lastly, the characteristics of each chromatographic mode in the analysis of derivatized sugars are described using various mobile phase compositions.

Computational simulations of the mass transfer zone in GS adsorption column packed with Fe3+ type ion exchanger

In this work, a mesoporous Fe³⁺ type ion exchanger (DOW-3) was used to adsorb the geniposide (GS) involved in gardenia yellow pigment waste water. To test its viability, the mass transfer zone (MTZ) in dynamic adsorption column that plays an important role in the future scale-up of the GS adsorption process was studied systematically. Simulation of the MTZ behavior under various operation conditions in a packed adsorption column enabled the predictions of breakthrough curves of GS for the mesoporous adsorbent. Several modes of mass transport and processes taking place simultaneously, such as permeation, convection, dispersion and adsorption equilibrium were incorporated in the proposed model. Modeling process firstly affected the behavior of MTZ when it formed and moved throughout the column, and then had a much greater impact on the shape of breakthrough curve in the simulation. The dynamics of MTZ were studied under different adsorption conditions such as various column heights, flow rates and inlet concentrations. Moreover, the post-processing technique and 3D visualization of MTZ simulation results were capable of demonstrating the expanding and progressing of the MTZ related to the adsorption isotherm. The basic findings of MTZ dynamics will be very useful for process scale up. Additionally, the effective molecule docking results obtained from this study, help us fully understand the contribution of various molecular forces in the adsorption mechanism.

A review of analytical procedures for the simultaneous determination of medically important veterinary antibiotics in environmental water: Sample preparation, liquid chromatography, and mass spectrometry

Medically important (MI) antibiotics are defined by the United States Food and Drug Administration as drugs containing certain active antimicrobial ingredients that are used for the treatment of human diseases or enteric pathogens causing food-borne diseases. The presence of MI antibiotic residues in environmental water is a major concern for both aquatic ecosystems and public health, particularly because of their potential to contribute to the development of antimicrobial-resistant microorganisms. In this article, we present a review of global trends in the sales of veterinary MI antibiotics and the analytical methodologies used for the simultaneous determination of antibiotic residues in environmental water. According to recently published government reports, sales volumes have increased steadily, despite many countries having adopted strategies for reducing the consumption of antibiotics. Global attention needs to be directed urgently at establishing new management strategies for reducing the use of MI antimicrobial products in the livestock industry. The development of standardized analytical methods for the detection of multiple residues is required to monitor and understand the fate of antibiotics in the environment. Simultaneous analyses of antibiotics have mostly been conducted using high-performance liquid chromatography-tandem mass spectrometry with a solid-phase extraction (SPE) pretreatment step. Currently, on-line SPE protocols are used for the rapid and sensitive detection of antibiotics in water samples. On-line detection protocols must be established for the monitoring and screening of unknown metabolites and transformation products of antibiotics in environmental water.

Reversed phase ion-pair chromatographic separation of sugar alcohols by complexation with molybdate ion

In this study, we developed a simple and sensitive reversed phase ion-pair chromatographic method for the analysis of C4-C6 sugar alcohols. The method is based on the on-line complexation of sugar alcohols with molybdate ion. The resulting dinuclear anionic complexes can be separated on a reversed-phase C18 column using tetrabutylammonium chloride as an ion-pairing reagent. The mobile phase (pH 3.1) consisted of 0.1 mM disodium molybdate, 1 mM hydrochloric acid and 0.4 mM tetrabutylammonium chloride - 10% v/v methanol. By complexing with molybdate ion, sugar alcohols can be detected by their UV absorption at 247 nm with high resolution and sensitivity. The quantification limits of the examined sugar alcohols calculated at S/N = 10 were 0.1 mM for erythritol and xylitol and 0.01 mM for arabitol, sorbitol, mannitol and dulcitol. The detector response was linear over three orders of magnitude of sugar alcohol concentration. The proposed method was successfully applied to measure sugar alcohols in health drinks, eyedrops and mouthwashes.

A polyacrylamide-based silica stationary phase for the separation of carbohydrates using alcohols as the weak eluent in hydrophilic interaction liquid chromatography

A hydrophilic interaction liquid chromatography (HILIC) stationary phase was prepared by a two-step synthesis method, immobilizing polyacrylamide on silica sphere particles. The stationary phase (named PA, 5μm dia) was evaluated using a mixture of carbohydrates in HILIC mode and the column efficiency reached 121,000Nm^-1. The retention behavior of carbohydrates on PA stationary phase was investigated with three different organic solvents (acetonitrile, ethanol and methanol) employed as the weak eluent. The strongest hydrophilicity of PA stationary phase was observed in both acetonitrile and methanol as the weak eluent, when compared with another two amide stationary phases. Attributing to its high hydrophilicity, three oligosaccharides (xylooligosaccharide, fructooligosaccharide and chitooligosaccharides) presented good retention on PA stationary phase using alcohols/water as mobile phase. Finally, PA stationary phase was successfully applied for the purification of galactooligosaccharides and saponins of Paris polyphylla. It is feasible to use safer and cheaper alcohols to replace acetonitrile as the weak eluent for green analysis and purification of polar compounds on PA stationary phase.

Multiplexing N-glycan analysis by DNA analyzer

Analysis of N-glycan structures has been gaining attentions over the years due to their critical importance to biopharma-based applications and growing roles in biological research. Glycan profiling is also critical to the development of biosimilar drugs. The detailed characterization of N-glycosylation is mandatory because it is a nontemplate driven process and that significantly influences critical properties such as bio-safety and bio-activity. The ability to comprehensively characterize highly complex mixtures of N-glycans has been analytically challenging and stimulating because of the difficulties in both the structure complexity and time-consuming sample pretreatment procedures. CE-LIF is one of the typical techniques for N-glycan analysis due to its high separation efficiency. In this paper, a 16-capillary DNA analyzer was coupled with a magnetic bead glycan purification method to accelerate the sample preparation procedure and therefore increase N-glycan assay throughput. Routinely, the labeling dye used for CE-LIF is 8-aminopyrene-1,3,6-trisulfonic acid, while the typical identification method involves matching migration times with database entries. Two new fluorescent dyes were used to either cross-validate and increase the glycan identification precision or simplify sample preparation steps. Exoglycosidase studies were carried out using neuramididase, galactosidase, and fucosidase to confirm the results of three dye cross-validation. The optimized method combines the parallel separation capacity of multiple-capillary separation with three labeling dyes, magnetic bead assisted preparation, and exoglycosidase treatment to allow rapid and accurate analysis of N-glycans. These new methods provided enough useful structural information to permit N-glycan structure elucidation with only one sample injection.

Validated HPAEC-PAD Method for the Determination of Fully Deacetylated Chitooligosaccharides

An efficient and sensitive analytical method based on high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was established for the simultaneous separation and determination of glucosamine (GlcN)₁ and chitooligosaccharides (COS) ranging from (GlcN)₂ to (GlcN)₆ without prior derivatization. Detection limits were 0.003 to 0.016 mg/L (corresponding to 0.4-0.6 pmol), and the linear range was 0.2 to 10 mg/L. The optimized analysis was carried out on a CarboPac-PA100 analytical column (4 × 250 mm) using isocratic elution with 0.2 M aqueous sodium hydroxide-water mixture (10:90, v/v) as the mobile phase at a 0.4 mL/min flow rate. Regression equations revealed a good linear relationship (R² = 0.9979-0.9995, n = 7) within the test ranges. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated HPAEC-PAD method was readily applied for the quantification of (GlcN)_1-6 in a commercial COS technical concentrate. The established method was also used to monitor the acid hydrolysis of a COS technical concentrate to ensure optimization of reaction conditions and minimization of (GlcN)₁ degradation.

Target-based metabolomics for the quantitative measurement of 37 pathway metabolites in rat brain and serum using hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry

Amino acids, neurotransmitters, purines, and pyrimidines are bioactive molecules that play fundamental roles in maintaining various physiological functions. Their metabolism is closely related to the health, growth, development, reproduction, and homeostasis of organisms. Most recently, comprehensive measurements of these metabolites have shown their potential as innovative approaches in disease surveillance or drug intervention. However, simultaneous measurement of these metabolites presents great difficulties. Here, we report a novel quantitative method that uses hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry (HILIC-UPLC-MS/MS), which is highly selective, high throughput, and exhibits better chromatographic behavior than existing methods. The developed method enabled the rapid quantification of 37 metabolites, spanning amino acids, neurotransmitters, purines, and pyrimidines pathways, within 6.5 min. The compounds were separated on an ACQUITY UPLC® BEH Amide column. Serum and brain homogenate were extracted by protein precipitation. The intra- and interday precision of all of the analytes was less than 11.34 %, and the accuracy was between -11.74 and 11.51 % for all quality control (QC) levels. The extraction recoveries of serum ranged from 84.58 % to 116.43 % and those of brain samples from 80.80 % to 119.39 %, while the RSD was 14.61 % or less for all recoveries. This method was used to successfully characterize alterations in the rat brain and, in particular, their dynamics in serum. The following study was performed to simultaneously test global changes of these metabolites in a serotonin antagonist p-chlorophenylalanine (PCPA)-induced anxiety and insomnia rat model to understand the effect and mechanism of PCPA. Taken together, these results show that the method is able to simultaneously monitor a large panel of metabolites and that this protocol may represent a metabolomic method to diagnose toxicological and pathophysiological states.

Overview of Methods for the Direct Molar Mass Determination of Cellulose

The purpose of this article is to provide the reader with an overview of the methods used to determine the molecular weights of cellulose. Methods that employ direct dissolution of the cellulose polymer are described; hence methods for investigating the molecular weight of cellulose in derivatized states, such as ethers or esters, only form a minor part of this review. Many of the methods described are primarily of historical interest since they have no use in modern cellulose chemistry. However, older methods, such as osmometry or ultracentrifuge experiments, were the first analytical methods used in polymer chemistry and continue to serve as sources of fundamental information (such as the cellulose structure in solution). The first part of the paper reviews methods, either absolute or relative, for the estimation of average molecular weights. Regardless of an absolute or relative approach, the outcome is a molecular weight average (MWA). In the final section, coupling methods are described. The primary benefit of performing a pre-separation step on the molecules is the discovery of the molecular weight distribution (MWD). Here, size exclusion chromatography (SEC) is unquestionably the most powerful and most commonly-applied method in modern laboratories and industrial settings.

Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications

A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation conditions for seven phenolic compounds was also achieved using reversed-phase HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and seven phenolic compounds could be separated and detected at 230 nm within 16 min.

Improved sulfoalkylbetaine-based organic-silica hybrid monolith for high efficient hydrophilic interaction liquid chromatography of polar compounds

A novel sulfoalkylbetaine-based zwitterionic organic-silica hybrid monolith was synthesized by using 3-dimethyl-(3-(N-methacrylamido) propyl) ammonium propane sulfonate (DMMPPS, neutral sulfoalkyl-betaine monomer). The added amount of zwitterionic monomer was significantly increased when DMMPPS was used instead of the conventionally used acidic sulfoalkyl-betaine monomer, that is, the N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium betaine, and this led to a significantly improved hydrophilicity of the monolith. The DMMPPS-based organic-silica hybridmonolith exhibited good mechanical stability and excellent separation performance. About ∼20 mμ plate height (corresponding to column efficiency of ∼50,000 plates/m) was obtained for nucleoside at the linear velocity of 1 mm/s. The proposed monolithic column was successfully applied to separate purines/pyrimidines, nucleotides, and tryptic digest of bovine hemoglobin in a nano-HILIC mode, and the results demonstrated that such monolith has the potential for separation of a variety of hydrophilic substances.

Amino-terminated ionic liquid modified graphene oxide coated silica composite stationary phase for hydrophilic interaction chromatography

IL@GO@SiO₂ composite was synthesized and revealed good separation for three kinds of strong polar and hydrophilic compounds in HILIC mode.

Characterization of size, structure and purity of serogroup X Neisseria meningitidis polysaccharide, and development of an assay for quantification of human antibodies

Serogroup X Neisseria meningitidis (MenX) has recently emerged as a cause of localized disease outbreaks in sub-Saharan Africa. In order to prepare for vaccine development, MenX polysaccharide (MenX PS) was purified by standard methods and analyzed for identity and structure by NMR spectroscopy. This study presents the first full assignment of the structure of the MenX PS using (13)C, (1)H and (31)P NMR spectroscopy and total correlation spectroscopy (TOCSY) and (1)H-(13)C heteronuclear single quantum coherence (HSQC). Molecular size distribution analysis using HPLC-SEC with multi-angle laser light scattering (MALLS) found the single peak of MenX PS to have a weight-average molar mass of 247,000g/mol, slightly higher than a reference preparation of purified serogroup C meningococcal polysaccharide. MenX PS tended to be more thermostable than serogroup A PS. A method for the quantification of MenX PS was developed by use of high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). A novel and specific ELISA assay for quantification of human anti-MenX PS IgG based on covalent linkage of the MenX PS to functionally modified microtitre plates was developed and found valid for the assessment of the specific antibody concentrations produced in response to MenX vaccination or natural infection. The current work thus provides the necessary background for the development of a MenX PS-based vaccine to prevent meningococcal infection caused by bacteria bearing this capsule.

Preparation of imidazole-functionalized silica by surface-initiated atom transfer radical polymerization and its application for hydrophilic interaction chromatography

A novel imidazole-functionalized stationary phase for hydrophilic interaction chromatography (HILIC) was prepared via surface-initiated atom transfer radical polymerization (SI-ATRP). 1-Vinylimidazole as a monomer was polymerized on the surface of initiator-immobilized silica by SI-ATRP using CuCl and 2,2'-bipyridyl as a catalyst. The graft chain length and polymer grafting density were controlled by varying the ratio of monomer to initiator. The resulting materials were characterized by elemental analysis and thermogravimetric analysis. Then, high-performance liquid chromatography separation of eight nucleobases/nucleosides was performed on the imidazole-functionalized chromatographic column in HILIC mode. The effects of mobile phase composition, buffer pH, and column temperature on the separation of nucleobases/nucleosides were investigated, and the retention mechanisms were studied. Chromatographic parameters were calculated, and the results showed that surface adsorption through hydrogen bonding and electrostatic interaction dominated the retention behavior of the solutes in HILIC mode. Lastly, the stationary phase was successfully used to determine the nucleobases and nucleosides from Cordyceps militaris.

Hydrophilic interaction chromatography in drug analysis

Hydrophilic interaction chromatography (HILIC) is an increasingly popular alternative to conventional HPLC for drug analysis. It offers increased selectivity and sensitivity, and improved efficiency when quantifying drugs and related compounds in complex matrices such as biological and environmental samples, pharmaceutical formulations, food, and animal feed. In this review we summarize HILIC methods recently developed for drug analysis (2006–2011). In addition, a list of important applications is provided, including experimental conditions and a brief summary of results. The references provide a comprehensive overview of current HILIC applications in drug analysis.

Carbon nanoparticles from corn stalk soot and its novel application as stationary phase of hydrophilic interaction chromatography and per aqueous liquid chromatography

Carbon nanoparticles (CNPs) (6-18 nm in size) were prepared by refluxing corn stalk soot in nitric acid. The obtained acid-oxidized CNPs are soluble in water due to the existence of carboxylic and hydroxyl groups. (13)C NMR measurement shows the CNPs are mainly of sp(2) and sp(3) carbon structure different from CNPs obtained from candle soot and natural gas soot. Furthermore, these CNPs exhibit unique photoluminescence properties. Interestingly, the CNPs might be exploited to immobilize on the surface of porous silica particles as chromatographic stationary phase. The resultant packing material was evaluated by high-performance liquid chromatography, indicating that the new stationary phase could be used in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes. The separation of five nucleosides, four sulfa compounds and safflower injection was achieved by using the new column in the HILIC and PALC modes, respectively.

Analysis of glycans derived from glycoconjugates by capillary electrophoresis-mass spectrometry

The high structural variation of glycan derived from glycoconjugates, which substantially increases with the molecular size of a protein, contributes to the complexity of glycosylation patterns commonly associated with glycoconjugates. In the case of glycoproteins, such variation originates from the multiple glycosylation sites of proteins and the number of glycan structures associated with each site (microheterogeneity). The ability to comprehensively characterize highly complex mixture of glycans has been analytically stimulating and challenging. Although the most powerful MS and MS/MS techniques are capable of providing a wealth of structural information, they are still not able to readily identify isomeric glycan structures without high-order MS/MS (MS(n) ). The analysis of isomeric glycan structures has been attained using several separation methods, including high-pH anion-exchange chromatography, hydrophilic interaction chromatography and GC. However, CE and microfluidics CE (MCE) offer high separation efficiency and resolutions, allowing the separation of closely related glycan structures. Therefore, interfacing CE and MCE to MS is a powerful analytical approach, allowing potentially comprehensive and sensitive analysis of complex glycan samples. This review describes and discusses the utility of different CE and MCE approaches in the structural characterization of glycoproteins and the feasibility of interfacing these approaches to MS.