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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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Pressure–Enhanced Liquid Chromatography as a Suitable Approach to Improve Selectivity for Large Molecule SeparationsPressure-enhanced liquid chromatography (PE-LC) offers a new approach for improving selectivity for large molecule separations. Examples shown here include short oligonucleotides in ion-pairing reversed-phase (IP-RP) liquid chromatography and larger nucleic acids in ion-exchange (IEX) chromatography.
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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.
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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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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.
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.
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Recent Advances in Hyphenated Chromatography and Mass Spectrometry Techniques and Their Impact on Late-Stage Pharmaceutical DevelopmentIn late-stage pharmaceutical development a new generation of high-resolution mass spectrometers and ion mobility mass spectrometers operate as orthogonal separation techniques and have greatly increased the ability to resolve impurities and increase the level of analytical information gained from a single analysis.
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Recent Advances in Hyphenated Chromatography and Mass Spectrometry Techniques and Their Impact on Late-Stage Pharmaceutical DevelopmentIn late-stage pharmaceutical development a new generation of high-resolution mass spectrometers and ion mobility mass spectrometers operate as orthogonal separation techniques and have greatly increased the ability to resolve impurities and increase the level of analytical information gained from a single analysis.
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Pressure Tuning: Increasing the Flexibility of Comprehensive Two-Dimensional Gas ChromatographyComprehensive two-dimensional gas chromatography (GC×GC) offers significant improvement for volatile chemical separation. Selecting suitable first (1D) and second dimension (2D) columns normally requires consideration of the chemical composition of a sample. Replacing one of these dimensions with a two-column ensemble (for example, 1D1 + 1D2 for the 1D column), provided with a pressure tuning makeup gas between them, varies the relative retentions of compounds before the modulation step according to the junction pressure. This makes it possible to alter the apparent polarity of the 1D ensemble, and this alters peak positions in the 2D GC×GC space. This article presents an account of studies that suggest this offers potential for improved operation for a GC×GC laboratory.
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Implementation of Methods Translation between Liquid Chromatography InstrumentationPharmaceutical research and development (R&D) organizations were early adopters who recognized the many benefits of UltraPerformance LC? (UPLC?) Technology including resolution, sensitivity, throughput, and productivity as compared to HPLC.
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Fast and Sensitive Analysis of Amino Acids Using Automated Pre-Column DerivatizationThe building blocks of peptides and proteins, amino acids, are present in animals, humans, and plants. The analysis of amino acids is of essential significance in several areas including food science, clinical diagnostics, and pharmaceutical products research. Classical liquid chromatography (LC) determination of amino acids is performed with sample pretreatment including pre-column as well as post-column derivatization to improve or enable spectroscopic detection.
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Stoichiometry of Intrinsically-Disordered Protein ComplexesIntrinsically-disordered proteins cannot be analyzed by SEC column calibration. SEC-MALS provides accurate molecular masses of these proteins and of their complexes with other proteins.
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Advances in Micro-Ultrahigh-Performance Liquid Chromatography–Mass Spectrometry in Residue and Contaminant AnalysisAdvances in nano-ultrahigh-performance liquid chromatography–mass spectrometry (nUHPLC) and micro–UHPLC (?UHPLC) are described and evaluated, with reference to the analysis of veterinary drugs and steroids in porcine meat and urine, respectively.
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Determination of Seven Sodium Alkyl Sulphates in Environmental Water by Ion-pair Chromatography with Suppressed Conductivity DetectionA simple and fast ion-pair chromatography method to detect sodium alkyl sulphates in environmental samples using conductivity detection is described.
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Nontargeted Screening for the Verification of Allergenic Ingredients and Perfume Authenticity by GC-ecTOF-MSIn this study, the experimental nontargeted screening approach and corresponding data analysis workflows—simultaneously using molecular ion information and structural information—are presented for the molecular identification and authenticity verification process from a brand perfume using GC–ecTOF-MS.
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Methods for Changing Peak Resolution in HPLC: Advantages and LimitationsThis article discusses useful approaches for the resolution of overlapping and superimposed peaks in HPLC.
