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Fundamental and Practical Aspects of Liquid Chromatography and Capillary Electromigration Techniques for the Analysis of Phenolic Compounds in Plants and Plant-Derived Food, Part 2: Capillary Electromigration TechniquesAnalytical separation techniques based on the differential migration velocities of analytes under the action of an electric field are gaining increasing acceptance for the analysis of phenolic compounds in edible and medicinal plants and in plant-derived food products. In Part 2 of this review article the authors discuss the fundamental principles and practical aspects of electromigration techniques, including capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC). The development of two-dimensional systems, performed by coupling either liquid chromatography (LC) with an electromigration technique or two electromigration techniques, operated under different separation mechanisms, is also discussed.
Latest:
Fundamental and Practical Aspects of Liquid Chromatography and Capillary Electromigration Techniques for the Analysis of Phenolic Compounds in Plants and Plant-Derived Food, Part 2: Capillary Electromigration TechniquesAnalytical separation techniques based on the differential migration velocities of analytes under the action of an electric field are gaining increasing acceptance for the analysis of phenolic compounds in edible and medicinal plants and in plant-derived food products. In Part 2 of this review article the authors discuss the fundamental principles and practical aspects of electromigration techniques, including capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC). The development of two-dimensional systems, performed by coupling either liquid chromatography (LC) with an electromigration technique or two electromigration techniques, operated under different separation mechanisms, is also discussed.
Latest:
Fundamental and Practical Aspects of Liquid Chromatography and Capillary Electromigration Techniques for the Analysis of Phenolic Compounds in Plants and Plant-Derived Food, Part 2: Capillary Electromigration TechniquesAnalytical separation techniques based on the differential migration velocities of analytes under the action of an electric field are gaining increasing acceptance for the analysis of phenolic compounds in edible and medicinal plants and in plant-derived food products. In Part 2 of this review article the authors discuss the fundamental principles and practical aspects of electromigration techniques, including capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC). The development of two-dimensional systems, performed by coupling either liquid chromatography (LC) with an electromigration technique or two electromigration techniques, operated under different separation mechanisms, is also discussed.
Latest:
Molecular Structure of Poly(Lactic-co-Glycolic acid) by SEC with Advanced DetectionThe macroscopic properties of material based on poly(D,L-lactic-co-glycolic acid) (PLGA) polymers are tunable by molar mass distribution and degree of branching, enabling optimization for applications in the pharmaceutical and medical industries. Size-exclusion chromatography followed by online multi-angle light scattering with intrinsic viscosity detection (SEC–MALS–IV) is an advanced analytical method for determining absolute molar mass distributions, identifying polymer conformation and quantifying branching. SEC–MALS–IV overcomes the errors that can be encountered in molar mass determined by conventional SEC, which arise from chemical composition and molecular structure, and provides comprehensive characterization of PLGA to facilitate the targeted development of optimized polymer.
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Optimization of Sample Preparation for Pesticide Analysis in Oil-Based Cannabis Products Using LipiFiltr®This application note outlines the performance benefits achieved with UCT’s LipiFiltr® cleanup cartridge for the analysis of pesticides in oil-based cannabis products using LC–MS/MS analysis.
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Analysis of Phospholipid Classes by iHILIC®-FusionPhospholipids (PLs) are the major components of cellular membranes. They are important for the functionality of membrane proteins or serve as precursors for second messengers. Several studies reveal the role of PL alterations in various diseases such as cancer (1). Therefore, it is crucial to identify and quantify PLs in complex biological samples for lipidomic studies and clinical research.
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Analysis of Polyethylene by Pyrolysis-GC×GC–MSThis application note shows the pyrolysis-GC×GC–HRMS profiles of crude oils for more detailed separations and more complete characterization of complex matrices, especially on the speciation of heteroatoms such as sulphur-containing compounds.
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Combining Sorptive Extraction with Two-Dimensional Gas Chromatography for the Flavour Profiling of MilkThis proof-of-principle study shows that polymer-based sorptive extraction probes, coupled with secondary focusing by thermal desorption and analysis by flow-modulated GC×GC–TOF-MS/FID, can be used to separate and identify flavour compounds in milk. As well as comparing the profiles of dairy and non-dairy milks, this article highlights the practical benefits of this sampling procedure, the ability of two-dimensional GC to physically separate components that would coelute in one-dimensional GC, and the use of software tools to improve workflow.
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Automated Multicolumn Purification of a Histidine-Tagged ProteinApproximately 40% of recombinant proteins that are purified use a histidine tag for easy capture. This article covers how to automate the purification of histidine-tagged proteins and how purification conditions can be optimized to an automated four-step purification scheme that uses affinity-, ion exchange-, and size-exclusion columns. Using a multistep purification scheme removes the manual steps that cause loss of precious proteins and take more time, like dialysis, collection, and reinjecting samples. The final purification scheme reduces a 3–4-day process to 11.5 h from start to finish, all while improving reproducibility, yield, and comparable purity.
Latest:
Automated Multicolumn Purification of a Histidine-Tagged ProteinApproximately 40% of recombinant proteins that are purified use a histidine tag for easy capture. This article covers how to automate the purification of histidine-tagged proteins and how purification conditions can be optimized to an automated four-step purification scheme that uses affinity-, ion exchange-, and size-exclusion columns. Using a multistep purification scheme removes the manual steps that cause loss of precious proteins and take more time, like dialysis, collection, and reinjecting samples. The final purification scheme reduces a 3–4-day process to 11.5 h from start to finish, all while improving reproducibility, yield, and comparable purity.
Latest:
Application of a GPC-LC–MS/MS Method for the Determination of 31 Mycotoxins in Edible OIlsGel Permeation Chromatography (GPC) is widely used for sample clean up in mycotoxin analysis. The most commonly described methods use GPC columns packed with SX-3 BioBeads suitable for cleaning Zearalenone, Aflatoxins, and Trichothesenes from edible oils and fatty matrices. Separation of Fumonisins from the oil fraction are inadequate with this column.
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Fast Analysis of Third-Generation Cephalosporins in Human Plasma by SPE and HPLC MethodsA fast, selective, and reproducible high performance liquid chromatography (HPLC) method was developed and validated for the analyses of third-generation cephalosporin antibiotics, namely, ceftriaxone, cefixime, and cefdinir in human plasma. The analysis was carried out on a 150 mm Ã- 4.6 mm, 5.0-µm C18 column. The mobile phase used was 80:20 (v/v) 50 mmM phosphate buffer (pH 5.0)–methanol at a flow rate of 1.0 mL/min with 230-nm UV detection.
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Detection of Pyrethroids in Surface Water and SedimentA sensitive method for quantitation of pyrethroids in surface water and sediment samples using GC?MS?MS is proposed.
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Molecular Weight Analysis of Glatiramer Acetate and Related Compounds by Size-Exclusion Chromatography with Multi-Angle Light Scattering Detection (SEC-MALS)A method was developed for the molecular weight characterization of heterogeneous polymer mixtures, such as heparins and glatiramer acetate, noting that single molecular structures are not adequate for creating a molecular weight calibration curve. That limitation is overcome in this work, which demonstrates method validation and application to process samples.
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Detection and Identification of Natural Antioxidants in Edible Oils Using LC Fractionation with Off-Line Effect-Based DetectionMultiple fractions can be tested in parallel with this fast method.
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Monoclonal Antibody Analysis (May 2023)This application note shows that a single column to be used for the analysis of a wide range of molecular sizes, from intact proteins and monoclonal antibodies to digested peptides.
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Epitope Mapping of an Interleukin Receptor for Three Therapeutic Antibodies by Hydrogen-Deuterium Exchange Mass SpectrometryAmong all the analytical techniques available for epitope mapping studies, hydrogen–deuterium exchange mass spectrometry (HDX-MS) is usually the fastest and easiest to carry out. We present here the epitope mapping of three distinct monoclonal antibody (mAb) candidates targeting the same antigen, an interleukin receptor. The goal is to establish the binding mode of these mAbs, and explain possible differences observed for in vitro binding and in vivo function.
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Systematic Evaluation of HILIC Stationary Phases for MS Characterization of OligonucleotidesHydrophilic interaction chromatography–mass spectrometry (HILIC-MS) offers a flexible and efficient alternative to ion-pairing reversed-phase liquid chromatography (IP-RPLC) for oligonucleotide analysis, with column selectivity and mobile phase pH being key factors in optimizing retention and detection.
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Disinfection Byproducts in Natural WatersThe occurrence of disinfection byproducts in natural waters poses a health risk for humans as well as aquatic organisms. This article presents a method, which was recently developed at the University of Arizona, in Tucson, Arizona, USA, for the fast and simultaneous determination of 15 regulated and unregulated disinfection byproducts.
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Advancing Gene Therapy: Enzyme Selection for Effective RNA Oligonucleotide MappingNew gene therapy modalities, such as CRISPR guide RNA (single guide ribonucleic acid [sgRNA]) and messenger RNA (mRNA), continue to make progress in both primate and first-in-human trials. As this progress builds, the industry remains accountable for characterizing these molecules to meet the requirements of regulatory authorities.
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Molecular Imprinting for Sample PreparationSample preparation is the most crucial step for the development of an analytical method. The main purpose of sample preparation is the extraction and preconcentration of the target analytes, as well as the removal of the matrix interferences, before their separation and determination. It is the most time consuming step that should be deliberately optimized to enhance extraction selectivity and detection capability. LLE and SPE, along with their variations, are usually applied for sample extraction and cleanup. MIPs can replace conventional sorbent materials in sample preparation techniques such as SPE, SMPE, and MSPD, offering increased selectivity over the target analytes. Attention is given in MISPE, which is mostly used to study MIP applications, as well as a commercially available technique.
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Can Chemistry Be Accessible For Students With Visual Impairment?This article presents a multimodal approach for students with severe visual impairment or blindness, to encourage them to learn more about chromatographic processes.
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Capitalizing on the Benefits of Ion Mobility for Metabolite IdentificationThe goal of metabolite identification groups is to de-risk compounds moving into development by ensuring they have favourable metabolic profiles before clinical trials are initiated. Liquid chromatography–mass spectrometry (LC–MS) is a well-established technology for this purpose, as a result of its ability to selectively and accurately distinguish drugs and their metabolites. Ion mobility spectrometry (IMS) can add another critical dimension of separation by improving spectral clarity and generating collision cross section (CCS) values to track metabolites across multiple analysis conditions. Modern software platforms have now evolved to solidify the value of IMS for the field of metabolite identification.
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A LEAN Approach for the Determination of Residual Solvents Using Headspace Gas Chromatography with Relative Response FactorsThis study demonstrates a new LEAN approach and method, where 25 solvents can be simultaneously determined based on predetermined relative response factors (RRFs) against an internal standard (decane) with only one injection of sample solution.
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Nonlinear Predictive Modelling Enables In Silico Optimization of Chromatographic Methods for Complex Stationary Phase‑Analyte InteractionsTo reach satisfactory results in terms of accurate retention time prediction, new in silico optimization approaches must be considered.
Latest:
A LEAN Approach for the Determination of Residual Solvents Using Headspace Gas Chromatography with Relative Response FactorsThis study demonstrates a new LEAN approach and method, where 25 solvents can be simultaneously determined based on predetermined relative response factors (RRFs) against an internal standard (decane) with only one injection of sample solution.
Latest:
A LEAN Approach for the Determination of Residual Solvents Using Headspace Gas Chromatography with Relative Response FactorsThis study demonstrates a new LEAN approach and method, where 25 solvents can be simultaneously determined based on predetermined relative response factors (RRFs) against an internal standard (decane) with only one injection of sample solution.
