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How to Build a GLP Bioanalytical LabOctober 2006. This month's "MS - The Practical Art" will interest those starting a new good laboratory practices (GLP) bioanalytical laboratory, reassessing an existing lab, or revamping a "spirit-of-GLP" laboratory to full GLP status.
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Simultaneous Separation of Pharmaceutical Counterions on a Reversed-Phase/Anion-Exchange/Cation-Exchange Tri-Mode HPLC ColumnSalt formation is a critical aspect in drug development and HPLC is an important tool for determination of pharmaceutical counterions.
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How To Buy Gas Calibration MixesIn January 2004, LCGC Europe published an article on methods for selecting pure gases for analytical applications. 1 Here, the authors expand on this topic by addressing questions regarding gas mixtures - defined simply as more than one gas in a cylinder.
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ExTech and HTC-9Is it possible to combine a serious scientific meeting together with social events and fun? Well if it is possible then the ExTech and HTC-9 meeting held in York, UK between 6?10 February came very close.
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Analysis of Volatile Bacterial Metabolites by Gas Chromatography–Mass SpectrometryA method for the identification of key volatile organic compound (VOC) markers associated with infection by Neisseria meningitidis bacteria by gas chromatography–mass spectrometry (GC–MS) was developed. Headspace samples of bacterial VOCs were trapped on triple-sorbent bed tubes and then thermally desorbed into a laboratory GC–MS system for separation. Identification was carried out by comparison of GC retention time and electron ionization mass spectra to the National Institute of Standards and Technology (NIST) database. Further confirmation was obtained by GC–MS of known standard chemicals. A total of 75 VOCs were detected, five of which can be considered key VOC markers for Neisseria meningitidis. These peaks were identified as 1,2-dimethylcyclopropane, 2-methylpropanal, methacrolein, N-2-dimethyl-1-propanamine, and 3-methylbutanal by the NIST database.
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Early International Symposia on Chromatography (50-Year Anniversary of the Chromatographic Society)October 2006. This year, the Chromatography Society is celebrating its 50-year anniversary. On the occasion of this anniversary, E.R. Adlard, one of the true pioneers of GC and a leading member of the organization, reports on the most important papers presented at the symposia in the first decade.
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In-Tube Solid-Phase Microextraction and On-Line Coupling with High-Resolution GCA novel device for coupling on-line in-tube SPME with capillary GC is presented by the guest authors and the method's application demonstrated for the analysis of contaminants in water.
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Ion Suppression: A Major Concern in Mass SpectrometryIn this tutorial, the mechanism and origin of ion suppression will be investigated, as well as ways to validate the presence, and circumvent or compensate for, the effects in LC-MS.
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Hydrophilic Interaction Capillary Electrochromatography for the Separation of Polar CompoundsThe authors introduce hydrophilic interaction capillary electrochromatography as a capillary column technique for the separation of polar compounds.
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High-Stakes Competition: Advances in Chromatography Stay Ahead of DopersDoping testing is now an accepted fact of sporting life - whether in major international competitions, such as the Olympics, or in regular events at the national level. Athletes who cheat by taking banned substances risk harming their careers and their health. They also bring their country and their sport into disrepute. A reliable and reproducible scientific system for doping testing, backed up by sanctions, helps fight the culture of drugs in sport so that athletes can participate on a level playing field.
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Retention Time Prediction Based on Molecular Structure in Pharmaceutical Method Development: A PerspectiveThe principal aim of this work was to provide a perspective with practical utility in streamlining the chromatographic method development in pharmaceutical industries based upon predicting the chromatographic retention times from molecular structures. Workflows were suggested with a focus on reversed-phase LC, IC, and HILIC as the three major techniques. Unlike HILIC, retention prediction in both reversed-phase LC and IC can benefit from the maturity of these techniques and the transparency of their retention mechanisms. In reversed-phase LC the solute coefficients in the hydrophobic subtraction model and in IC the a and b values in the linear solvent strength model can be the subject of modelling with their subsequent use in retention prediction. A workflow for HILIC can be based on the design of experiments approach, to account for all major contributors to the retention mechanism, and direct correlation of experimental retention times to the molecular descriptors.
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Hydrophilic Interaction Capillary Electrochromatography for the Separation of Polar CompoundsThe authors introduce hydrophilic interaction capillary electrochromatography as a capillary column technique for the separation of polar compounds.
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Precise Sample Preconcentration Coupled with Automated SamplingDionex has developed an autosampler with very precise sample preconcentration capabilities. When analyte detection is no longer possible even with a large loop injection, sample preconcentration (loading a sample through a concentrator column and eluting the concentrate) is used.
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Single Calibrant Quantification with HPLC — Fact or Fantasy?This article assesses the extent to which some familiar HPLC detectors can provide reliable quantitative analytical measurements when no suitable primary reference standard exists. The advantages and limitations of two candidate detector schemes are discussed ? evaporative light-scattering detection (ELSD) and chemiluminescent nitrogen detection (CLND). It was found that when the ERETIC (Electronic REference To access In-vivo Concentrations) method in proton NMR was used as a "gold standard" reference procedure the ability of CLND to provide reliable single calibrant quantification is superior to ELSD. Furthermore, ELSD showed bias towards underestimation of chromatographically-resolved impurities, resulting in an overestimation of analyte purity.
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Hydrophilic Interaction Capillary Electrochromatography for the Separation of Polar CompoundsThe authors introduce hydrophilic interaction capillary electrochromatography as a capillary column technique for the separation of polar compounds.
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Peak Fronting, Column Life and Column ConditioningAlthough there are other possible causes, the most common source of fronting peaks is a disturbance in the column packing bed. The fix is straightforward: replace the column.
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Hydrophilic Interaction Capillary Electrochromatography for the Separation of Polar CompoundsThe authors introduce hydrophilic interaction capillary electrochromatography as a capillary column technique for the separation of polar compounds.
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Chromatography for Bioanalytical ChemistsThis article looks at current practices in bioanalytical chemistry by examining and critically assessing the various parameters that can be altered to achieve high-speed results with high resolution in LC–MS applications. The decision to opt for gradient or isocratic elution is also discussed.
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Single Calibrant Quantification with HPLC — Fact or Fantasy?This article assesses the extent to which some familiar HPLC detectors can provide reliable quantitative analytical measurements when no suitable primary reference standard exists. The advantages and limitations of two candidate detector schemes are discussed ? evaporative light-scattering detection (ELSD) and chemiluminescent nitrogen detection (CLND). It was found that when the ERETIC (Electronic REference To access In-vivo Concentrations) method in proton NMR was used as a "gold standard" reference procedure the ability of CLND to provide reliable single calibrant quantification is superior to ELSD. Furthermore, ELSD showed bias towards underestimation of chromatographically-resolved impurities, resulting in an overestimation of analyte purity.
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PS-DVB Monolithic Columns Applied in A Microcolumn Switching Set-up for the Analysis of Peptides and ProteinsPolystyrene-divinylbenzene (PS-DVB) trap columns have been evaluated for microcolumn switching applications. In contrast to traditional stationary phases, which consist of packed particles, the monolithic separation medium is made of a continuous, rigid polymeric rod with a porous structure. The absence of intraparticular void volume increases separation efficiency, allowing for faster separations. Column lifetime is higher compared to packed columns.
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Analysis of Volatile Bacterial Metabolites by Gas Chromatography–Mass SpectrometryA method for the identification of key volatile organic compound (VOC) markers associated with infection by Neisseria meningitidis bacteria by gas chromatography–mass spectrometry (GC–MS) was developed. Headspace samples of bacterial VOCs were trapped on triple-sorbent bed tubes and then thermally desorbed into a laboratory GC–MS system for separation. Identification was carried out by comparison of GC retention time and electron ionization mass spectra to the National Institute of Standards and Technology (NIST) database. Further confirmation was obtained by GC–MS of known standard chemicals. A total of 75 VOCs were detected, five of which can be considered key VOC markers for Neisseria meningitidis. These peaks were identified as 1,2-dimethylcyclopropane, 2-methylpropanal, methacrolein, N-2-dimethyl-1-propanamine, and 3-methylbutanal by the NIST database.
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Evaluating Analytical Instrumentation Using the Golf Score Card ToolThe use of a simple Excel-based "Golf Score Card" tool can facilitate assessments and instrument acquisistion decisions by collating and weighting the relative importance of the many criteria that impact the final purchase decision. The authors describe this process.
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An Improved Analytical Temperature-Rising Elution Fractionation System for Automated Analysis of PolyethylenesThe authors describe a system for automated analytical temperature-rising elution fractionation that uses the built-in differential refractometer of a commercial gel-permeation chromatography instrument and a stop-flow method for sample crystallization.
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Innovations in Food Analysis — Analysis of Peptides, Additives and FlavoursThe analysis of peptides and additives using a new HPLC innovative column technology, Pathfinder, was shown. For the analysis of flavours in lemon juice GC–MS with a new MS library, FFNSC, with linear retention indices was used.
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Evaluation of Polar-Embedded and Polar-Endcapped C12-C18 Stationary Phase Vulnerabilities Toward Highly Nucleophilic Compounds: A Case StudyHere the authors discuss an ion-pair, gradient HPLC method, developed for cycloserine-related substances using a polar, amide-embedded C18 column. Other polar-embedded and polar-edcapped columns are evaluated in equivalence studies.
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Precise Sample Preconcentration Coupled with Automated SamplingDionex has developed an autosampler with very precise sample preconcentration capabilities. When analyte detection is no longer possible even with a large loop injection, sample preconcentration (loading a sample through a concentrator column and eluting the concentrate) is used.
