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Achieving Optimum GC Separation – Designing New Capillary Column Stationary Phases Using Computer ModelingBy calculating optimal stationary-phase composition and physical parameters, column developers can construct columns that provide the exact separation requirements desired by analysis or current methods.
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Indirect Suppressed-Conductivity Ion ChromatographyThe authors demonstrate a new detection method for various anions of weak acids separated by ion chromatography and point out the main advantages of this method.
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Gas Chromatography and Ion Mobility Spectrometry: A Perfect Match?The basic operating principles of ion mobility spectrometers (IMS), their resulting strengths and weaknesses, and why both perfectly align with the capabilities and requirements of gas chromatographs are discussed.
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Optimizing PFAS Sample Preparation Efficiency and Laboratory Cleanliness for EPA Method 1633U.S. Environmental Protection Agency (EPA) Method 1633 signifies a pivotal shift in per- and polyfluoroalkyl substance (PFAS) determination, extending beyond drinking water.
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Quantifying Smoke Taint in California Wines by Immersive Sorbent Sheet Extraction Prior to Direct Analysis in Real-Time Mass Spectrometry (DART-MS)Measuring volatile phenols in wine is essential in ensuring superior wine quality. A new analytical technique, called solid-phase mesh-enhanced sorption from headspace (SPMESH), was modified with direct immersion (DI) conditions and coupled to direct analysis in real time–mass spectrometry (DART–MS) to be used to detect smoke taint in winemaking.
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Achieving Optimum GC Separation – Designing New Capillary Column Stationary Phases Using Computer ModelingBy calculating optimal stationary-phase composition and physical parameters, column developers can construct columns that provide the exact separation requirements desired by analysis or current methods.
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Validation of HPLC-DAD Based Stability Indicating Assay Method for Ornidazole in Periodontal Polymeric Hydrogel: Robustness Study using Quality by Design (QbD) ApproachIn the present study, a gradient reversed-phase high-performance liquid chromatography (RP-HPLC) method has been designed and validated to quantify ornidazole (OZ) in the marketed formulation (oral gel) with the application of QbD.
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Approaches to Accelerate Liquid Chromatography Method Development in the Laboratory Using Chemometrics and Machine LearningThe authors explore computer-aided workflows and machine learning, aimed at optimizing LC parameters, focusing on kinetic and thermodynamic aspects, and proposes closed-loop optimization strategies.
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Real-Time Stack Emission Measurements of Non-Traditional Odorous Species from an Industrial Processing FacilitySelected ion flow tube mas spectrometry (SIFT–MS) offers real-time measurements directly from air without chromatography or sample preparation, providing an attractive alternative for these hard-to-measure volatile organic compounds.
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Per- and Polyfluoroalkyl Substances (PFAS) or Interference? Using High-Resolution Mass Spectrometry as an Investigative Tool in Food AnalysisMatrix interferences can impact routine analysis with triple quadrupole methods for monitoring and quantifying PFAS in food.
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LC–MS/MS for the Quantification of Tau and Phosphorylated Tau in Alzheimer’s Disease Patients’ CSFQuantification of Tau proteoforms in cerebrospinal fluid (CSF) could be useful to diagnose neurodegenerative diseases. LC–MS/MS results can help explain the underlying molecular mechanisms of disease evolution.
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Analytical Advantages of Highly Stable Stationary Phases for Reversed-Phase LCDuring the past five years, many manufacturers of HPLC columns have focused on improving stationary phase stability and reproducibility. In this study, the authors use a variety of test solutes to compare the efficiency, selectivity, and hydrophobic retention mechanisms of five commercially available HPLC columns based silica, alumina, zirconia, and polystyrene cross-linked with divinylbenzene as the support.
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Oligonucleotide quality control using LC-UV-MSHPLC coupled with negative ESI-MS provides a reliable method with unique capabilities for separation and identification of (therapeutic) oligonucleotides.
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Improving on AOAC 2001.02: GOS Determination in Foods Using HPAEC–PADAn improved method for determining total galactooligosaccharide (GOS) content in food and supplements using high performance anion exchange chromatography with pulsed amperometric detection is described.
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Aggregate and Fragment Analysis in Therapeutic Monoclonal Antibodies Using On-Line Size-Exclusion Chromatography with Native Mass SpectrometrySize-exclusion chromatography (SEC), with the use of ammonium acetate buffer, can be coupled on-line to electrospray ionization MS for the characterization of size variants of therapeutic monoclonal antibodies (mAbs). A quadrupole time-of-flight (QTOF) MS system was employed, and the MS method was optimized to achieve favorable sensitivity for high-mass detection, while maintaining the structural integrity of the aggregates (or high molecular weight species) and fragments (or low molecular weight species).
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Breaking the Rules: Two- and Three-Dimensional Chromatography with Four Dimensions of Mass SpectrometryTwo-dimensional liquid chromatography (2D-LC) allows much greater resolution of peaks than is possible in a classical single dimensional separation. For the next development in separations, we employed 2D-LC in two highly orthogonal dimensions of separation with four mass spectrometers for detection, with parallel detection in each dimension. We have further broken ground by using three dimensions of separation with four mass spectrometers, using two parallel second dimensions.
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Go With the Flow: Thinking About Carrier Gas Flow in GCSuccessful GC analysis requires careful control of carrier gas. Here, we explain how to measure and control flow rate, use constant pressure vs. constant flow, and more.
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Stability and Recovery Influences of Benzo[a]pyrene, Benzo[a]anthracene, Benzo[b]fluoranthene, and Chrysene during Sample Preparation of Plant MatricesQuantification of European Union (EU)-priority polycyclic aromatic hydrocarbons (PAHs) in plant matrices is a crucial task. Various methods for enrichment and preconcentration, such as the preloaded-pipette tip solid‑phase extraction (SPE) (1), are available. Nevertheless, analyte recovery as a result of homogenization, sample preparation, and extraction are rarely discussed in the field of phytopharmacy. This study deals with the recovery in dry plant extracts, which are typically used in phytopharmaceuticals and reflect the actual polycyclic aromatic hydrocarbon content in the commercially available end product (2). The aim of this study was to monitor benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene loss of spiked samples as a result of commonly-used sample pretreatment, extraction, filtering, and evaporating techniques in 1:1 (v/v) cyclohexane–ethyl acetate primulae flos and sambuci flos dry extracts. Results showed that improper sample preparation can lead to false results. In the case of benzo[a]pyrene with a deviation of 155% from the theoretical true value.
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Comparison of PFAS Sample Preparation Between WAX + Dispersive GCB and WAX/GCB Cartridges from Water and Soil Extracts Per Draft EPA 1633How to speed up sample prep time and equivalent acccuracy and precision.
