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Improving HPLC Separation of PolyphenolsThis article highlights a number of recent developments in HPLC for polyphenol analysis.
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Qualitative and Quantitative Metabolite Identification for Verapamil in Rat Plasma by Sub-2-μm LC Coupled with Quadrupole TOF-MSAn effective metabolite identification study should ideally include both qualitative and quantitative information that for both identifying metabolites, and determining the rate of clearance and the metabolic routes of the parent drug. Liquid chromatography–mass spectrometry (LC–MS) is considered the standard analytical technique for metabolite identification studies. To date, however, qualitative and quantitative information has always been obtained from two separation platforms: quadrupole time-of-flight (QTof) MS for the exact mass full-scan qualitative study, and tandem quadrupole MS for the multiple reaction monitoring (MRM) quantitative study. With advancements to QTof instrumentation, specifically, recent improvements in sensitivity and dynamic range, it is now possible to perform both qualitative and quantitative experiments on a single QTof mass spectrometer. This article describes a workflow that allows simultaneous qualitative and quantitative metabolite identification studies to be..
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Determining Organotin Compounds in Marine Water and Sediment Samples using HS-SPME–GC–FIDThis article describes a fast, simple and clean procedure to determine three organotin compounds (monobutyltin, dibutyltyin and tributyltin) in environmental samples.
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Using LC–oa-TOF MSE with a Multivariate Statistical Sample Statistical Sample Profiling Strategy to Distinguish Chinese Red Ginseng from Korean Red GinsengBoth Chinese ginseng and Korean ginseng are similar plant species and undergo similar handling procedures when harvested and processed for sale. Despite their similarities, Korean ginseng commands a higher price than Chinese ginseng on the open market and is believed to produce different clinical effects than Chinese ginseng. Chinese researchers are now employing new techniques on the two varieties of ginseng to understand their chemical differences. HPLC/UV-based strategies for distinguishing the two types of ginseng have proven to be mostly ineffective due to lack of resolution. Using UltraPerformance liquid chromatography/orthogonal acceleration (oa)–TOF mass spectrometry and exact mass measurement, the authors developed a high-resolution method using multivariate statistical analysis for separating and identifying differences between Chinese ginseng and Korean ginseng at the molecular level.
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The Use of Hollow Fibers in Liquid-Phase MicroextractionIn this installment, the subject of LPME is reviewed, with emphasis on the use of hollow fibers.
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Per- and Polyfluorinated Alkylsubstances (PFAS) from Dairy and Fish Using QuEChERS, SPE, and LC–MS/MSThe analysis of per- and polyfluorinated alkyl substances (PFAS) in food samples, along with an optional additional solid-phase extraction (SPE) clean-up for even more sensitive liquid chromatography tandem mass spectrometry (LC–MS/MS), is demonstrated in this article.
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Sampling Volatiles From Fragranced Consumer Products Using High-Capacity Sorptive ExtractionThis study describes the analysis of fragranced washing detergent and washing powder using probe-based headspace and immersive sorptive extraction, in conjunction with analysis by thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). As well as discussing the differences between the two samples, the analyte ranges covered by headspace and immersive sampling are compared.
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Gaining New Insights in Advanced Polymeric Materials Using Comprehensive Two-Dimensional Liquid ChromatographyTwo-dimensional LC, with advanced modulation techniques, can advance the analysis of advanced polymeric materials, assisting in characterizing copolymer composition heterogeneity and identifying ingredients in complex products.
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High Throughput Extraction of Melamine using EVOLUTE CX Mixed-mode SPE PlatesThe use of EVOLUTE CX mixed-mode columns provides high and consistent recoveries across a range of complex matrices, from biological fluids to milk products. The dual retention mechanism ensures that matrix components such as proteins, salts and phospholipids are removed, resulting in lower ion suppression and accurate analysis.
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Static Headspace GC–MS Detection of Residual Solvents—A Possible Simultaneous Identification and Quantitation MethodA new procedure is proposed that provides identity parameters for headspace-applicable residual solvent Class 1 and Class 2 compounds addressed in the current US Pharmacopeia <467> method.
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HSS HPLC Columns: An Additional Option for Transferring Methods between HPLC and UPLC TechnologyAs UPLC users convert or replace their existing HPLC systems with UPLC systems there is a transition period where a method must be run on both platforms. Thus, having the same particle substrate and bonded phases available in HPLC and UPLC particle sizes can significantly ease the burden of method development and transfer from one platform to another. In addition to the ethylene bridged hybrid (BEH) particle, three new high strength silica (HSS) stationary phases for HPLC applications are introduced. Scalability between both column diameter and particle size is demonstrated on both UPLC and HPLC instrumentation.
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Advances in Sample Preparation for Food AnalysisSample preparation is a crucial part of the analysis of foodstuffs. Current sample preparation techniques used in food analysis are reviewed and the advantages and drawbacks of each one are discussed.
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Improved Analysis of FAMEs using Gas Chromatography with Vacuum Ultraviolet Detection (GC–VUV)The powerful characteristics of gas chromatography (GC) with VUV (vacuum ultraviolet) detection for the analysis of saturated and unsaturated fatty acids are described.
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Simultaneous Headspace-GC–FID Analysis for Methanol and Ethanol in Blood, Saliva and Urine: Validation of Method and Comparison of SpecimensA simultaneous headspace-GC–FID method was validated to establish methanol and ethanol assessment in blood, urine and saliva.
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Comparison of Liquid–Liquid Extraction (LLE) and Supported Liquid Extraction (SLE): Equivalent Limits of Quantification with Smaller Sample VolumesIn this application, we demonstrate the use of supported liquid extraction (SLE) for the extraction of beta blockers and NSAIDS from plasma compared with traditional liquid–liquid extraction. SLE was demonstrated to yield consistent LOQs using lower sample volumes.
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Selective Detection with UV Spectroscopy in Gas ChromatographyUV spectroscopy is an effective approach for tandem or parallel detection in gas chromatography, particularly in separations that require narrow bandwidths, such as GCxGC.
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Popular Cell Expression Systems in the Biotechnology IndustryThe authors describe the most common cell-based protein expression systems and purification strategies used in the biotechnology industry.
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Improving HPLC Separation of PolyphenolsPractical HPLC, HILIC and RP-LC methods of analysing common food and beverages containing polyphenols are presented.
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Using LC–oa-TOF MSE with a Multivariate Statistical Sample Statistical Sample Profiling Strategy to Distinguish Chinese Red Ginseng from Korean Red GinsengBoth Chinese ginseng and Korean ginseng are similar plant species and undergo similar handling procedures when harvested and processed for sale. Despite their similarities, Korean ginseng commands a higher price than Chinese ginseng on the open market and is believed to produce different clinical effects than Chinese ginseng. Chinese researchers are now employing new techniques on the two varieties of ginseng to understand their chemical differences. HPLC/UV-based strategies for distinguishing the two types of ginseng have proven to be mostly ineffective due to lack of resolution. Using UltraPerformance liquid chromatography/orthogonal acceleration (oa)–TOF mass spectrometry and exact mass measurement, the authors developed a high-resolution method using multivariate statistical analysis for separating and identifying differences between Chinese ginseng and Korean ginseng at the molecular level.
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ADME/Pharmacokinetic Studies from Serum and Plasma: Improvements in Sample Preparation and LC–MS Analysis of Therapeutic OligonucleotidesThe paramount problem in performing absorption, distribution, metabolism, and excretion (ADME)/pharmacokinetic studies of therapeutic oligonucleotides revolves around inefficient and labor-intensive sample preparation. These traditional methods require multiple steps - liquid–liquid extraction (LLE) and solid-phase extraction (SPE) - to extract therapeutic oligonucleotides from serum and plasma for liquid chromatography–mass spectrometry (LC–MS) analysis and thus are not practical for clinical studies with large numbers of samples. Furthermore, these methods tend to yield low recoveries and poor reproducibility. This article presents a revolutionary new method for performing sample cleanup of therapeutic oligonucleotides from serum and plasma. The method extracts many types of therapeutic oligonucleotides from biological matrices in a rapid four-step SPE protocol that eliminates the need for LLE and can be automated for large sample sets. In the testing presented, different..
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Metabolite Profiling Applications in Early Drug DiscoveryMetabolite profiling in drug discovery can contribute significantly at the lead optimization stage in two main application areas. The first is the identification of major metabolites, which provides medicinal chemists with information on the metabolic "soft spots." These soft spots are locations on the molecule particularly susceptible to metabolic modification, which can contribute to high pharmacokinetic clearance. This information then can be used to optimize the structure of a lead compound or chemical series to slow the rate of metabolism and therefore reduce hepatic clearance. This improves the absorption, distribution, metabolism, and excretion (ADME) properties of the compound, such as bioavailability, exposure (as measured by area under the curve), and half-life. Through iterative optimization of the structure and timely generation of metabolism data following each structural modification, pharmacokinetic properties can be improved while maintaining activity against the therapeutic target.
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Meeting the Surge in Demand for Seafood Screening on the Gulf CoastThe threat to human health posed by the recent oil spill has created a pressing need for high-throughput seafood analysis to ensure that it does not contain dangerous levels of polycyclic aromatic hydrocarbons (PAHs) and to allow the earliest possible reopening of the fisheries. Adapting QuEChERS sample preparation technology to this application, combined with the use of preconfigured PAH gas chromatography–mass spectrometry analysis systems, can provide the ability to process in a timely manner the enormous number of samples that will be generated by the ongoing testing program.
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Towards Automated Routine Analysis of the Distribution of Trace Elements in Single Cells Using ICP-MSAnalysis of the compositional variation in living cells is essential for understanding biological processes. Single-cell elemental analysis by triple-quadrupole ICP-MS is emerging as a selective, highly sensitive, and potentially high-throughput technique for the study of constitutive elements, and uptake of metallodrugs (or metal-containing nanomaterials) in single cells.
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Increasing Productivity of ADME Studies Using Accurate Mass TechnologyA new time-of-flight mass spectrometer was evaluated for performing simultaneous metabolic stability measurement and metabolite identification with ultrahigh-pressure liquid chromatography. Six representative compounds (clomipramine, diclofenac, imipramine, haloperidol, verapamil, and midazolam) were incubated in rat liver microsomes at a more physiologically relevant substrate concentration (1 ?M). High-resolution full-scan and product-ion spectra were acquired in a single injection using generic methodology. Quantitative clearance of the parent was measured using the full-scan data. Major metabolites were identified using the accurate mass product ion spectra. High scanning speed allowed for a sufficient number of data points to be collected across the chromatographic peak for quantitative analysis. Sensitivity was sufficient for obtaining meaningful kinetics with a 1 ?M initial substrate concentration.
Latest:
Using LC–oa-TOF MSE with a Multivariate Statistical Sample Statistical Sample Profiling Strategy to Distinguish Chinese Red Ginseng from Korean Red GinsengBoth Chinese ginseng and Korean ginseng are similar plant species and undergo similar handling procedures when harvested and processed for sale. Despite their similarities, Korean ginseng commands a higher price than Chinese ginseng on the open market and is believed to produce different clinical effects than Chinese ginseng. Chinese researchers are now employing new techniques on the two varieties of ginseng to understand their chemical differences. HPLC/UV-based strategies for distinguishing the two types of ginseng have proven to be mostly ineffective due to lack of resolution. Using UltraPerformance liquid chromatography/orthogonal acceleration (oa)–TOF mass spectrometry and exact mass measurement, the authors developed a high-resolution method using multivariate statistical analysis for separating and identifying differences between Chinese ginseng and Korean ginseng at the molecular level.
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GCxGC with Fluidic Modulation on Enantioselective Oil AnalysisDescribes a novel approach for the enantioselective separation of spearmint oil incorporating a fluidic modulation system.
