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Analyzing Multisegmented Block Copolymers by SEC-MALS-IV“Click” chemistry is a class of efficient and selective reactions that is characterized by quantitative yields, tolerance to a broad range of functional groups, facile experimental setup, and minimal synthetic workup. This class of reactions combines particularly well with controlled radical polymerization methods, such as atom transfer radical polymerization (ATRP), and the two techniques have been prolifically employed for the synthesis of a wide variety of novel polymeric materials, including (multi) block copolymers, stars, brushes, and gels. This note describes the analysis of multisegmented block copolymers prepared by click-coupling of block copolymers synthesized by ATRP.
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Analyzing Multisegmented Block Copolymers by SEC-MALS-IV“Click” chemistry is a class of efficient and selective reactions that is characterized by quantitative yields, tolerance to a broad range of functional groups, facile experimental setup, and minimal synthetic workup. This class of reactions combines particularly well with controlled radical polymerization methods, such as atom transfer radical polymerization (ATRP), and the two techniques have been prolifically employed for the synthesis of a wide variety of novel polymeric materials, including (multi) block copolymers, stars, brushes, and gels. This note describes the analysis of multisegmented block copolymers prepared by click-coupling of block copolymers synthesized by ATRP.
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Simultaneous Determination of Methylxanthines and Cotinine in Human Plasma by Solid-Phase Extraction Followed by LC–MS-MSA multiresidue method has been developed and validated for the analysis of methylxanthines (caffeine and its metabolites) and cotinine in human plasma.
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Identifying "Known Unknowns" in Commercial Products by Mass SpectrometryThe identification of nontargeted species in environmental and commercial samples by mass spectrometry can be very difficult. In this article, authors from Eastman Chemical Company describe their systematic approach for the identification of nontargeted species using nominal and accurate mass data, searching both mass spectral and "spectra-less" databases.
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Recent Advances in Two-Dimensional Liquid Chromatography for Pharmaceutical and Biopharmaceutical AnalysisThis is an exciting time for 2D-LC, as the expanding community of users works to develop creative solutions involving 2D-LC to solve analytical challenges that are very difficult or impossible to solve by conventional means.
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Two-Dimensional Liquid Chromatography Does More Than Increase Peak CapacityTwo-dimensional liquid chromatography (2D-LC) is drawn out of the chromatographic toolbox if resolution for compounds of interest is insufficient. Recently, several studies have started to highlight 2D-LC as a tool of choice to streamline analytical workflows to increase automation making them less time-consuming. This article highlights two proven cases where 2D-LC does more than simply increase peak capacity.
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Analysis of PFAS in Locally Acquired Food ContainersThe combination of an untargeted approach using ultrahigh pressure liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC–QTOF) and a targeted approach using UHPLC–tandem mass spectrometry (MS/MS) are presented as an ideal method for detecting per- and polyfluroalkyl substances (PFAS) in fast-food packaging.
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Separation Science in Drug Development, Part 4: Quality ControlThis fourth and last instalment in the “Separation Science in Drug Development” series provides an overview of modern practices of quality control in small-molecule drug development, including activities such as setting specifications, method validation and transfer, release and stability testing, and authoring chemistry, manufacturing, and controls (CMC) sections of regulatory filings.
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Going Beyond the Requirements of US EPA Method TO-15: Cryogen-Free Monitoring of Trace-Level “Air Toxics” at High HumidityThis study describes the gas chromatography–mass spectrometry (GC–MS) analysis of trace-level “air toxics” in humidified cannister air, using cryogen-free preconcentration technology. We show that this method is able to detect 65 target compounds ranging from propene to naphthalene, with method detection limits as low as 0.7 pptv in SIM mode, making it compliant both with standard TO-15 methods, and with “trace TO-15” methods stipulating lower detection limits.
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Application of Paper Strip Extraction in Combination with LC–MS-MS in PharmacokineticsRecent advances in sampling techniques in the pharmaceutical industry sparked significant interest in applying improvements to extraction methods for greater analyte detection and quantitation.
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Enhancing Peptide Mapping Sequence Coverage Through an Automated Dual Protease DigestTrypsin is one of the most commonly used proteases in peptide mapping protocols because of its high level of specificity. However, trypsin alone is not always sufficient for full sequence coverage. In this article, the authors detail how trypsin was combined with chymotrypsin to overcome this, and the benefits of an automated platform.
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15th International Symposium on Hyphenated Techniques in Chromatography and Separation Technology (HTC-15)A preview of HTC-15, which will be held at Cardiff City Hall, Cardiff, United Kingdom, from 24–26 January 2018.
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Innovations In Sample Preparation: A Virtual Symposium*Live: Friday, June 18, 2021 at 1pm BST| 8am EDT* A special one-day symposium —chaired by Jared Anderson, a key opinion leader in the field of sample preparation and a member of the LCGC’s Editorial Advisory Board (EAB) — will highlight state-of-the art advances in sample preparation and will cover a wide range of topics *On Demand Until June 18, 2022*
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Highlights from the 52nd International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2024)This “Column Watch” installment presents many of the highlighted topics and trends observed at the 52nd International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2024).
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Using Benzoyl Chloride Derivatization to Improve Small-Molecule Analysis in Biological Samples by LC–MS/MSIn metabolomics, LC–MS is a popular technique because of its ability to separate a wide range of metabolites, but the presence of many highly polar analytes in these samples poses a challenge. Benzoyl chloride derivatization can be a practical solution, improving both sensitivity and selectivity.
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Comparing the Chemical Profiles of Plant-Based and Traditional Meats Using GC–MS-Based MetabolomicsUntargeted GC–MS metabolomics with sample derivatization is shown here to be effective for measuring the chemical profiles of traditional and plant-based meat products.
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Gas Chromatography–Mass Spectrometry Characterization of Vegetable Oil–Derived Potent Antimicrobial AgentsUnder a suitable thermal oxidation regime, vegetable oils yield a mixture of volatile and semivolatile organics that exhibit very high antimicrobial activities against a variety of microbial species. Volatile and semivolatile products were characterized with GC–MS using electron ionization and chemical ionization. The thermal oxidation of vegetable oils resulted in the formation of an array of short and medium-chain acids, aldehydes, and ketones that act synergistically to yield a potent antimicrobial disinfectant.
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Gas Chromatography–Mass Spectrometry Characterization of Vegetable Oil–Derived Potent Antimicrobial AgentsUnder a suitable thermal oxidation regime, vegetable oils yield a mixture of volatile and semivolatile organics that exhibit very high antimicrobial activities against a variety of microbial species. Volatile and semivolatile products were characterized with GC–MS using electron ionization and chemical ionization. The thermal oxidation of vegetable oils resulted in the formation of an array of short and medium-chain acids, aldehydes, and ketones that act synergistically to yield a potent antimicrobial disinfectant.
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Mass Spectrometry Techniques to Unravel the Heterogeneity of GlycoproteinsSince glycans are responsible for bioactivity, solubility, immunogenicity, and clearance rate from circulation, it is vital to have a detailed map of glycans in therapeutic glycoproteins. Detailed glycoprotein structural analysis must be able to identify the peptide sequence where the glycans are attached as well as the structure of the glycan portion, including oligosaccharide sequence and glycosyl linkages. This article details methods for mass spectrometry experiments on both released glycans (“glycomics”), as well as on intact glycopeptides (“glycoproteomics”) using electron transfer dissociation, high-energy collision dissociation, and collision-induced dissociation fragmentation pathways, which are needed to fully elucidate the structure of glycoproteins.
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Evaluating Substance Use via Wastewater Analysis: An Overview of Analytical WorkflowsWastewater analysis has become an established approach for retrieving additional epidemiological information about the use of illicit drugs, alcohol, and tobacco at the population level. Here, we present an overview of the recent analytical frameworks and workflows for target and suspect analyses using low- and high-resolution mass spectrometry and discuss the latest advances in wastewater-based epidemiology (WBE).
