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Prevention is Better Than Cure: An Alternative Approach in Sample Preparation of Complex SamplesCombining a membrane with a solid sorbent can improve selectivity and save time in sample preparation.
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Using GC–MS to Observe Changes in the Essential Oil Concentrations in Cedar Tree (Juniperus virginiana) Leaves During a Drought YearA look at how the concentration of essential oils in cedar leaves is affected by changes in temperature and the amount of rainfall
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Comprehensive Fragrance Profiling of Ginger, Wintergreen, and Rosemary Essential Oils by GC–TOF-MS with Soft Electron IonizationThis study demonstrates that GC–TOF-MS can be a useful approach to generate comprehensive fragrance profiles of essential oils. Peak deconvolution enables discrimination between closely eluted compounds, and soft electron ionization, assisted by comparison of ion ratios, makes it possible to discriminate between isomeric monoterpenes with very similar mass spectra at conventional 70-eV ionization energies.
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Sensitivity of Comprehensive Two-dimensional Gas Chromatography (GCXGC) Versus One-dimensional Gas Chromatography (1D GC)In this article, the sensitivity of two-dimensional gas chromatography coupled to two different detectors - a time-offl ight mass spectrometer (GCXGC–TOF-MS) and a fl ame ionization detector (GC?GC–FID) - was compared to the sensitivity of conventional one-dimensional gas chromatography (GC–TOF-MS and GC–FID) by determining method detection limits (MDLs) for a series of different compounds with different polarities.
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Ultratrace Quantitive Analaysis of Catalyst Poisoners Using a Dedicated GC–MS AnalyserA dedicated GC– MS analyser was developed to address the increasing need for more sensitive catalyst poisoner analysis. The system combines the separation power and robustness of a classic backflush configuration with the selectivity and sensisitivitiy of mass spectrometry.
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Planar Chromatography Versus Column Chromatography: A Performance ComparisonIt is hypothesized that in particular cases, conventional planar chromatography provides a more effective and robust system than column chromatography with regard to separation efficiency and peak distribution of mixtures composed of low-retarded analytes. Under similar reversed-phase experimental conditions, a regular distribution of thin-layer chromatography (TLC) spots of four natural estrogens (estetrol, estriol, 17?-estradiol, and estrone) corresponds to strong irregular dispersion of peaks in chromatograms generated by high performance liquid chromatography. In both cases, the efficiency of separation was assessed using simple optimization criteria such as selectivity (?min) and resolution (Rs min). The distribution of chromatographic spots was evaluated using the relative resolution product (r). The results revealed that an excellent separation of the components of interest could be achieved easily using simple nonforced and isocratic TLC. Such an interesting property of planar chromatography is mainly driven by the nonlinear relationship between k and Rf retention factors. This article also reports the practical advantages of TLC for the separation of estrogenic steroid mixtures at different temperatures.
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Ultratrace Quantitative Analysis of Catalyst Poisoners Using a Dedicated GC-MS AnalyzerCan databases of column characteristics be used to help with HPLC column selection ahead of method development?
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Enantiomer and Topoisomer Separation of Acidic Compounds on Anion-Exchanger Chiral Stationary Phases by HPLC and SFCQuinine- and quinidine-derived anion-exchanger chiral stationary phases have proven to be versatile in enantiomer separation of acidic compounds in HPLC. In this article, the authors demonstrate their performance in specific HPLC applications involving enantiomer resolution and topoisomer separation.
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Taking Advantage of Sub-2μm Core-Shell Particles for Ultra-Fast and Efficient Urinary Excretion ProfilingUrinary excretion profiling is a key element in the pharmokinetic characterization of new chemical entities (NCEs). Recent advances in ultra-high performance liquid chromatography (UHPLC) column technology offer improved results for liquid chromatography tandem mass spectrometry (LC–MS¬–MS) analysis, enabling rapid quantification of specific drugs and their metabolites in biological matrices.
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Advantages of HILIC Mobile Phases for LC–ESI–MS–MS Analysis of NeurotransmittersThe aim of this work was to find the optimal conditions to achieve sufficient limits of detection (LOD) that would permit the detection of neurotransmitters by LC–MS–MS in biological samples. An optimized HILIC–ESI–MS–MS system for the analysis of the 12 selected compounds was proposed.
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Developing a UHPLC Method for UV-based Detection and Quantification of Primary Aromatic Amines in Low ConcentrationsThis application demonstrates that stringent sensitivity requirements for the detection of potentially harmful primary aromatic amines can be fulfilled when using an Agilent 1290 Infinity LC system equipped with the 1290 large volume injection kit.
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Rapid and Specific Determination of Contaminants, By-Products, and Additives in Insulating Mineral Oils with Tandem Mass SpectrometryThe use of electrospray ionization–mass spectrometry for rapid and specific determination of the widely used metal deactivators Irgamet-30 and Irgamet-39 is demonstrated here.
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Robustness Modelling in Ultrahigh-Pressure Liquid Chromatography MethodsMany workers in pharmaceutical laboratories are unable to change any aspect of their methods, although they often encounter severe problems and create many out-of-specification (OoS) results. They are particularly afraid to investigate these problems from a chromatographic perspective in case they generate new unforeseen problems. In the literature, however, there are numerous examples showing that it is worthwhile trying to understand the reasons for “unexplainable” behaviour in ultrahigh-pressure liquid chromatography (UHPLC) using modelling. By using modelling, problems can be recognized and often eliminated with legal operations according to the allowed tolerance limits mentioned in pharmacopoeia descriptions. The following article aims to show that “visual chromatographic modelling” can be a useful aid.
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An Improved LC–MS–MS Method for the Determination of Clenbuterol in Human UrineA sensitive method that reduces the number of false-positive results
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Probing Aqueous Surfaces by TOF-SIMSA breakthrough using a microfluidic interface to conduct sensitive time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and study liquid surfaces in situ under vacuum conditions is described here.
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Ambient Ionization MS Analysis of Swabs Used for Explosives DetectionAn analysis of the capabilities of direct analysis in real time (DART) and desorption electrospray ionization (DESI) sources for the analysis of contaminated fabrics
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On- and Off-Line Coupling of Separation Techniques to Ambient Ionization Mass SpectrometryA review highlighting the combination, or potential combination, of various separation methods with ambient ionization mass spectrometry
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Strategies for Rapid Chiral HPLC Method Development for Pharmaceutical AnalysisAutomated column and mobile phase screening is the current trend in the pharmaceutical industry to develop chiral methods. This study presents comprehensive strategies for automated rapid chiral HPLC method development including normal-phase, reversed-phase and polar organic phase separation modes.
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Strategies for Rapid Chiral HPLC Method Development for Pharmaceutical AnalysisAutomated column and mobile phase screening is the current trend in the pharmaceutical industry to develop chiral methods. This study presents comprehensive strategies for automated rapid chiral HPLC method development including normal-phase, reversed-phase and polar organic phase separation modes.
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Analysis of Nicotine Alkaloids and Impurities in Liquids for e-Cigarettes by LC–MS, GC–MS, and ICP-MSThe development of various analytical MS methods to investigate the chemical composition of liquids used in electronic cigarettes and characterize their quality is presented in this study.
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Retention and Selectivity of Aromatic Hydrocarbons with Polar Groups in Ternary Reversed-Phase–HPLC Systems with Tetrahydrofuran as ModifierThe variation in selectivity of aromatic hydrocarbons with bisubstituted polar groups is investigated in systems consisting of C18 stationary phase and ternary eluents. The solutions of the ternary eluents were obtained by mixing binary solvents (organic modifier + water) of similar eluent strength. Acetonitrile, methanol and tetrahydrofuran were the organic modifiers applied. The influence of the organic solvent type and its concentration in the ternary mobile phase on retention and selectivity of the solutes is discussed. An approach previously presented by our group was adapted to explain the selectivity changes.
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How to Tackle an Unknown: Notes from the Fourth Method Development Olympics at CoSMoSPut yourself in their spot: How would you tackle analyzing a bag of gummy bears that showed up on your lab bench? Here, we offer some insights from the very capable finalists at The Conference on Small Molecule Science (CoSMoS), which was held in August 2015 in San Diego, California.
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Combining Novel and Traditional Ionization Methods for Mass Spectrometry for More Comprehensive AnalysesNovel ionization processes provide gas-phase ions of a wide variety of materials using MS. These simple and sensitive methods operate from solution or a solid matrix. Both manual and automated platforms are described that allow rapid switching between the ionization methods of MAI, SAI, vSAI, and conventional ESI.
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Ultratrace Quantitative Analysis of Catalyst Poisoners Using a Dedicated GC-MS AnalyzerCan databases of column characteristics be used to help with HPLC column selection ahead of method development?
Latest:
Using GC–MS to Observe Changes in the Essential Oil Concentrations in Cedar Tree (Juniperus virginiana) Leaves During a Drought YearA look at how the concentration of essential oils in cedar leaves is affected by changes in temperature and the amount of rainfall
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Hexavalent Chromium Determination HamiltonAnalysis of chromium species is made challenging due to the nature of the element and diverse sample matrices
