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The 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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Capillary gas chromatography (GC) is a well-established separation technique. Rick Parmely reviews some of the capillary column basics by investigating a standard test mixture and observing some of the chromatographic effects that can affect peak response, peak shape and column bleed. He provides guidelines for obtaining the best performance from a capillary column. He discusses peak tailing, column overload, ghost peaks and column bleed and speculates on "when to give up." He concludes with a set of fundamental steps to be used in achieving better GC analyses.

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The 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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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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Biologists entering liquid chromatography?mass spectrometry (LC?MS) from a background of general LC rarely use their mass spectrometer to its full potential. Isotope peaks offer huge possibilities both in semi-quantitative interpretation of structure and in quantitative labelling studies. This article examines charge state, "easy" isotopes, such as chlorine, the slightly harder problem of sulphur compounds, and finally looks at a method for improved measurement of heavy labels in a metabolic study.

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As environmental legislation becomes more stringent, the need to deliver quantitative results in shorter times and greater volumes is necessary for routine environmental analysis. Most of the high-throughput screening methods used to analyze pharmaceutical compounds are, however, useless for environmental monitoring. This is because these methods primarily aim to retrieve as much information from a single sample using the broadest range of techniques. The chromatographic separation process is considered to be the bottleneck in the process. This is not the situation for environmental procedures, in which the bottleneck is the sample preparation step and is usually very tedious and time-consuming.

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This article provides an overview of the most recent advances in the field of chiral and achiral separations in SFC. This involves research focused on the most critical parameters in SFC separations, but also on practical issues such as the serial coupling of columns.

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The authors test and compare performance of three types of LC–MS systems for precision, linearity, selectivity, accuracy, and sensitivity in the quantitation of drug impurities.

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This article describes the use of a 96-well, solvent-resistant filtration plate for total drug analysis in blood plasma.

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The development of chiral column technology since the review in 2008 is discussed by Thomas Beesley.

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Size exclusion chromatography (SEC) coupled to light-scattering, viscometer and refractive index detectors is a common technique used for the characterization of polymers. In this article the solution conformations of two chimeric IgG3 antibodies were studied using this coupled triple detection technique. Conclusions indicate that the results allow hydrodynamic modeling of the antibody structures.

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Size exclusion chromatography (SEC) coupled to light-scattering, viscometer and refractive index detectors is a common technique used for the characterization of polymers. In this article the solution conformations of two chimeric IgG3 antibodies were studied using this coupled triple detection technique. Conclusions indicate that the results allow hydrodynamic modeling of the antibody structures.

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A 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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Measurement of chiral purity is a necessary means of quality control for drug substances that exhibit chiral centers. This article describes a simple and practical approach to setting up system suitability and validation for chiral purity assays.

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This installment of "Sample Prep Perspectives" discusses microdialysis sampling and the opportunities and challenges it presents. The guest authors look at microdialysis theory and equipment and describe potential applications...

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The 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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The 50th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2022) returns to the USA this summer.

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As environmental legislation becomes more stringent, the need to deliver quantitative results in shorter times and greater volumes is necessary for routine environmental analysis. Most of the high-throughput screening methods used to analyze pharmaceutical compounds are, however, useless for environmental monitoring. This is because these methods primarily aim to retrieve as much information from a single sample using the broadest range of techniques. The chromatographic separation process is considered to be the bottleneck in the process. This is not the situation for environmental procedures, in which the bottleneck is the sample preparation step and is usually very tedious and time-consuming.

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This application note will demonstrate a GC–MS analysis of common polybrominated diphenyl ether (PBDE) congeners. An optimized method will allow the Clarus GC–MS to provide ample separation and high yields of all PBDE congeners. The extended mass range of the Clarus 500 MS and high-mass calibration will produce mass spectra with very high levels of accuracy.

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The 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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The authors introduce hydrophilic interaction capillary electrochromatography as a capillary column technique for the separation of polar compounds.

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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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Protein unfolding and aggregation can be serious considerations when designing laboratory and preparative chromatographic purification steps. This problem has been studied most thoroughly within the contexts of reversed-phase chromatography and hydrophobic interaction chromatography. However, there are currently no robust methods for resin selection capable of predicting adsorbed-phase protein stability as a function of amino acid sequence, secondary or tertiary structure, or resin characteristics.

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This article describes a software solution for automating the chromatographic method validation process starting from experimental planning, data acquisition and processing, through final report generation in a seamless manner. All experimental planning and calculations are accomplished within the chromatography data software and, thus, are structurally validated, secure, and audit trailed. Highlights of the software are provided, including benefits to the analyst. The analysis of important method validation characteristics such as linearity, accuracy, and precision is automated. These characteristics and their acceptance criteria can be captured in a method template, which adheres to the company's standard operating procedure. This template method can then be used repeatedly by other scientists in the organization, hence, eliminating the need to create a new experimental plan each time a new validation is conducted.

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An important prerequisite of a good sampling procedure for skin sebum is its reproducibility.

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A 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.