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Choosing an Optimal Co-Solvent for Method Development in Supercritical Fluid Chromatography (SFC) for the Whelk-O®1, RegisPack®, and RegisCell® Chiral Stationary PhasesThe majority of the samples in this study and other studies show that a majority of compounds can be separated by the use of the three most common alcohols: IPA, CH3OH, and ethanol. Solubility becomes a crucial factor in preparative chromatography. Combinations of solvents can be used to improve solubility when the chosen co-solvent has poor solubility of the compound in question.
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Determination of Chlorophenols in Water According to U.S. EPA Method 528Determination and quantification of water contamination by phenols using the Dionex AutoTrace 280 SPE instrument.
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Multi-Dimensional ChromatographyThe Wednesday afternoon session on multi-dimensional chromatography includes two talks from instrument vendors.
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Simultaneous Determination of Methotrexate and Sulphasalazine in Plasma by HPLC–DADHere we describe a simple and robust high performance liquid chromatography–diode array detection (HPLC–DAD) method for the simultaneous determination of methotrexate (MTX) and sulphasalazine (SSZ) from plasma. MTX and SSZ are used in combination for the treatment of rheumatoid arthritis. Using two detector wavelengths, 304 nm for MTX and 358 nm for SSZ, we were able to selectively quantitate both analytes during the same chromatographic run. The method was validated using quality control samples for critical analytical performance criteria of recovery, reproducibility, selectivity, accuracy, and precision.
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Simultaneous Determination of Methotrexate and Sulphasalazine in Plasma by HPLC–DADHere we describe a simple and robust high performance liquid chromatography–diode array detection (HPLC–DAD) method for the simultaneous determination of methotrexate (MTX) and sulphasalazine (SSZ) from plasma. MTX and SSZ are used in combination for the treatment of rheumatoid arthritis. Using two detector wavelengths, 304 nm for MTX and 358 nm for SSZ, we were able to selectively quantitate both analytes during the same chromatographic run. The method was validated using quality control samples for critical analytical performance criteria of recovery, reproducibility, selectivity, accuracy, and precision.
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Targeting Specific Matrix Interferences for Sample PreparationThis article describes the evolution of traditional solid-phase extraction (SPE) into new techniques that are customized to the characteristics of specific matrices, including the removal of β-glucuronidase from urine samples and the removal of phospholipids and proteins from plasma samples.
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Enantiomeric Separation of Proton Pump Inhibitors Using Polysaccharide-Based Chiral Stationary Phases in Reversed-Phase HPLC ConditionsThe chiral analysis and purification of proton pump inhibitors (PPIs) has become a popular topic as more of these drugs fall out of patent protection each year. Due to their wide range of enantiomeric selectivity, a set of polysaccharide-based chiral stationary phases (CSPs) was screened to identify methods for the successful enantioseparation of four benzimidazoles; rabeprazole, lansoprazole, omeprazole, and pantoprazole.
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Matrix-Assisted Laser Desorption-Ionization Imaging Mass Spectrometry for Direct Tissue AnalysisA summary of the most recent advances in sample preparation, instrumentation, and data-processing techniques for MALDI-IMS
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Rapid Quantitation of PFAS in Non-Potable WatersThe presence of per- and polyfluoralkyl substances (PFAS) in water is an important health and environmental concern. Liquid chromatography–mass spectrometry (LC–MS) has been established as the most suitable technology for monitoring these substances. A method is described, using EPA 8327, for PFAS analysis in groundwater, surface water, and wastewater.
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Improved Analysis of Polyfluorinated Alkyl Substances in Environmental Samples Using Optimized ASTM Method 7968/7979This article evaluates ASTM D7979-16 for the “direct” analysis of 30 PFCs and 19 mass-labeled surrogates. Instead of using solid-phase extraction, the PFCs were solubilized in a methanol–water mix and filtered if necessary, and the sample was injected into a LC–MS/MS system.
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N-Nitrosamines in Rubber Teats, Soothers, and ToysThis note looks at the analysis of N-nitrosamines in rubber teats, soothers, and toys, with specific focus on babies and young children under UK method BS EN 71-12:2016.
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Gas Chromatography Detection of Nitrosamines in Food and BeveragesThis article discusses the detection of N-nitroso compounds (NOC) in a range of different food and beverages.
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Fast and Robust Analysis of Drugs of Abuse Using Direct Exposure Probe on the Pegasus HTDirect exposure probe (DEP) coupled to the Pegasus HT, time-of-flight mass spectrometer, was used for the identification of synthetic cannabinoids in MTN-series compounds.
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Fast and Robust Analysis of Drugs of Abuse Using Direct Exposure Probe on the Pegasus HTDirect exposure probe (DEP) coupled to the Pegasus HT, time-of-flight mass spectrometer, was used for the identification of synthetic cannabinoids in MTN-series compounds.
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Modern Supercritical Fluid Chromatography — Possibilities and PitfallsThere has been a revival of supercritical fluid chromatography (SFC) in recent years, especially in the chiral preparative field, but also more recently in the analytical area. However, SFC is considerably more complex than liquid chromatography (LC), mainly because of the compressibility of the mobile phase. One can say that SFC is a “rubber variant” of LC where everything considered constant in LC varies in SFC. In this review, we go through advances in theory, instrumentation, and novel applications.
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Glyphosate Analysis in Soy Beans, Corn, and Sunflower Seeds by HPLC with Post-Column Derivatization and Fluorescence DetectionGlyphosate is a broad-spectrum herbicide widely used around the world. Monitoring of glyphosate in crops and water is mandated in many countries.
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An Open-Source Simulator for Exploring HPLC TheoryDespite the utility of high performance liquid chromatography (HPLC) simulators, we found that all the free and low-cost simulators were outdated or had extremely limited functionality, so we created one that addressed these shortcomings. We developed a sophisticated, open-source HPLC simulator that is available for free as well as a version for Android users called "HPLC Simulator." Here we discuss a few questions that the simulator can help answer: Why are peaks narrower in gradient elution? What is gradient delay and how does it affect a separation?
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An Open-Source Simulator for Exploring HPLC TheoryDespite the utility of high performance liquid chromatography (HPLC) simulators, we found that all the free and low-cost simulators were outdated or had extremely limited functionality, so we created one that addressed these shortcomings. We developed a sophisticated, open-source HPLC simulator that is available for free as well as a version for Android users called "HPLC Simulator." Here we discuss a few questions that the simulator can help answer: Why are peaks narrower in gradient elution? What is gradient delay and how does it affect a separation?
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High-throughput Multiplexing Gas ChromatographyThis article describes a technique based on pseudo-random injection sequences to perform rapid sample injections.
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Method Robustness and Reproducibility for Monoclonal Antibody Purity AnalysisThe benefits of a robustness assessment for the analysis of a NIST mAb using a wide pore C4 LC column are described.
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A Sensitive and Cost-Effective LC–MS-MS Method for Determination of 1α,25-Dihydroxyvitamin D3 in Human PlasmaThe biologically active form of vitamin D is an important analytical target in both research and clinical practice.
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Determination of the Relative Prevalence of Lurasidone Metabolites in Urine Using Untargeted HRMSFor lurasidone treatment adherence testing, an untargeted high-resolution mass spectrometry method was employed, using known positive human urine samples to identify the lurasidone metabolites and their relative abundance in urine.
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Rapid Determination of 24 Synthetic and Natural Cannabinoids for LC–MS-MS Screening in Natural Products and Drug Inspection ApplicationsMarijuana, the common or slang term for cannabis in its herbal form, is one of the most widely used illicit drugs in the world.
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A Sensitive and Cost-Effective LC–MS-MS Method for Determination of 1α,25-Dihydroxyvitamin D3 in Human PlasmaThe biologically active form of vitamin D is an important analytical target in both research and clinical practice.
