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Gas Chromatography and Ion Mobility Spectrometry: A Perfect Match?The basic operating principles of ion mobility spectrometers (IMS), their resulting strengths and weaknesses, and why both perfectly align with the capabilities and requirements of gas chromatographs are discussed.
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Method Development for Reversed-Phase Separations of Peptides: A Rational Screening Strategy for Column and Mobile Phase Combinations with Complementary SelectivityThis review article summarizes the results obtained from the combined efforts of a joint academic and industrial initiative to solve the real-life challenge of determining low levels of peptide-related impurities in the presence of the related biologically-active peptide at a high concentration.
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Identification of Microplastics in Environmental Monitoring Using Pyrolysis–GC–MS AnalysisPyrolysis–gas chromatography–mass spectrometry has advantages for the analysis of environmental microplastic samples compared to other leading analytical methods, including spectroscopic techniques.
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Supplementary Info: Non-aqueous Ion-Exchange Chromatography Using High Acid‑base Concentration: A Strategy for Purifying Non-crystalline Pharmaceutical IntermediatesThis information is supplementary to the article “Non-aqueous Ion-Exchange Chromatography Using High Acid‑base Concentration: A Strategy for Purifying Non-crystalline Pharmaceutical Intermediates” that was published in the March 2022 issue of LCGC Asia Pacific.
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The Origin and Implications of Artifact Ions in Bioanalytical LC–MSAlthough well known, the extent of adduct ion formation in LC–ESI-MS/MS, and the implications for quantitative analysis and analyte characterization are not fully appreciated. We explore this problem and explain the implications for reproducibility, quantitative and qualitative analyses, and DDA and DIA.
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Another 10 Ways to Spoil a CE SeparationThis month's "CE Currents" continues an examination of problems that users may find in routine CE work. Readers can avoid these problems by adopting the working practices suggested by the authors.
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Quantitative Metrics to Properly Describe Solute Elution in Size-Exclusion ChromatographyThe purpose of this short tutorial article is to review the terms and official nomenclatures for size-exclusion separations and to provide some guidance and recommendations for practicing chromatographers. The interconversion between the different metrics is explained and some examples are presented.
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Nontargeted Screening for the Verification of Allergenic Ingredients and Perfume Authenticity by GC-ecTOF-MSIn this study, the experimental nontargeted screening approach and corresponding data analysis workflows—simultaneously using molecular ion information and structural information—are presented for the molecular identification and authenticity verification process from a brand perfume using GC–ecTOF-MS.
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Applying LC and LC–MS Methods to the Characterization and Analysis of rAAVA look at the LC and LC–MS methods that are helping to overcome challenges in sample analysis, and how this can make adeno‑associated virus (AAV)–based gene therapy more accessible.
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A Quick and Accurate High Performance Liquid Chromatography (HPLC) Method to Determine the Amount of Trimethylamine in Fish Oil Softgels and Multivitamin Softgels Containing Fish OilA HPLC method was developed to measure trimethylamine in fish oil supplements, to determine if the level of this compound affects product quality attributes such as rancidity.
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Superheated Water: A New Look at Chromatographic Eluents for Reversed-Phase HPLCThe authors describe the results they've achieved by using water heated to 100–240 ºC as a liquid eluent for reversed-phase HPLC instead of an organic modifier. They point out that this alternative avoids many of the problems – toxicity, flammability, and cost – associated with organic modifiers.
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Simulated Moving Bed Chromatography for Preparative SolutionsThis month's "Column Watch" describes moving bed chromatography and how the concept is realized in the form of simulated moving bed chromatography. Also included is an inside look at instrumentation, method development, and applications for industrial purifications.
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Py-GC-MS Investigation of Pyrolysis Behaviours and Decomposition Products of α- and β-2,7,11-Cembratriene-4,6-DiolsThe study of the thermal behaviour and pyrolysis products of these terpenoids could possibly suggest flavour precursors that could be used to provide specific flavours to tobacco.
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Gas Chromatography–Mass Spectrometry (GC–MS) with Cold Electron Ionization (EI): Bridging the Gap Between GC–MS and LC–MSGas chromatography–mass spectrometry (GC–MS) with cold electron ionization (EI) is based on interfacing the GC and MS instruments with supersonic molecular beams (SMB) along with electron ionization of vibrationally cold sample compounds in SMB in a fly-through ion source (hence the name cold EI). GC–MS with cold EI improves all the central performance aspects of GC–MS. These aspects include enhanced molecular ions, improved sample identification, an extended range of compounds amenable for analysis, uniform response to all analytes, faster analysis, greater selectivity, and lower detection limits. In GC–MS with cold EI, the GC elution temperatures can be significantly lowered by reducing the column length and increasing the carrier gas flow rate. Furthermore, the injector temperature can be reduced using a high column flow rate, and sample degradation at the cold EI fly-through ion source is eliminated. Thus, a greater range of thermally labile and low volatility compounds can be analyzed. The extension of the range of compounds and applications amenable for analysis is the most important benefit of cold EI that bridges the gap with LC–MS. Several examples of GC–MS with cold EI applications are discussed including cannabinoids analysis, synthetic organic compounds analysis, and lipids in blood analysis for medical diagnostics.
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Gas Chromatography Tandem Mass Spectrometry Analysis of Ethylene Oxide: An Emerged Contaminant in Seeds and SpicesTwo alternative approaches based on gas chromatography coupled to tandem mass spectrometry (GC–MS/MS) were developed to control the maximum residue limit of the banned insecticide, ethylene oxide (EtO), and its transformation product, 2-chloroethanol (2-CE).
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Low-Resolution or High-Resolution MS for Clinical and Forensic Toxicology: Some Considerations from Two Real CasesHow can low-resolution mass spectrometry (LRMS) and high-resolution (HR) MS work together to provide unambiguous results in clinical and forensic toxicology?
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Optimizing Control of Pump-Related Biopharma-Production ProcessesThis application note will illustrate how a new integrated pump controller is giving users automated control of pump operations in critical biopharma applications.
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Comparison of PFAS Sample Preparation Between WAX + Dispersive GCB and WAX/GCB Cartridges from Water and Soil Extracts Per Draft EPA 1633How to speed up sample prep time and equivalent acccuracy and precision.
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Profiling Free Naphthenic Acids in Produced Water Using Gas Chromatography Coupled to High Resolution Accurate Mass SpectrometryIn this instalment of “Column Watch”, a simple method for profiling free naphthenic acids in produced water by GC–MS is proposed.
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Investigating Decomposition Odor in a Tropical Climate by Comprehensive Two-Dimensional Gas Chromatography (GC×GC) Coupled with Mass Spectrometry (MS) and Flame Ionization Detection (FID)Decomposing animal tissue releases volatile organic compounds (VOCs), of interest in forensic science. We describe the use of GC×GC–qMS/FID retrofitted with a reverse fill/flush (RFF) flow modulator for analyzing these VOCs in a tropical climate.
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Analysis of UV-Treated Mushrooms: Dietary Source of Vitamin D2?In our study, a fast and sensitive liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) method for the determination of vitamin D2 in fresh mushrooms and its metabolite 25(OH)D2 in the blood of volunteers regularly consuming UV-treated mushrooms has been introduced.
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Optimized Explosives Analysis Using Portable Gas Chromatography–Mass Spectrometry for Battlefield ForensicsWhen explosives are encountered on the battlefield, the use of portable GC–MS is valuable for the detection and confirmatory identification of pre- and post-detonation threats. In addition, this technique provides information about the source of explosives based on the detection and identification of trace-level chemicals in the sample. The data presented here confirm this capability.
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Exploring the Implementation of Compact Chromatographic Instrumentation in Common Analytical WorkflowsCompact instrumentation offers important advantages for many workflows, as illustrated by these examples.
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Moving Toward Green and Sustainable Sample PreparationMicroextraction techniques have evolved since their appearance three decades ago, moving toward the use of greener and sustainable materials and solvents.
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The Effects of Inner Surface Roughness of Microbore Column Blanks on Column PerformanceThe efficiencies of microbore-2 columns, which are prepared from blanks that have a wide variety of inner surface roughness, drop sharply when the size of individual surface roughness features approaches the particle size of the packing material. The results suggest that two categories of packed column structure relate to the surface features and yield high and low efficiency columns. This installment of "Column Watch" discusses this conclusion in terms of the stability of an agglomerated layer of packing particles on the blank wall when subjected to shear forces during column packing.
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Combined Chromatographic and Spectrometric Approaches for Cleaning Verification of Small-Molecule Pharmaceutical Compounds in the Manufacturing EnvironmentWe assess recent advances in cleaning verification methods for small-molecule pharmaceuticals, and propose a workflow.
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Liquid Chromatographic Peak Purity Assessments in Forced Degradation Studies: An Industry PerspectiveThis review article discusses scientific rationales and current best practices in the pharmaceutical industry for performing chromatographic peak purity assessments (PPA). These activities are associated with the development and validation of liquid chromatographic (LC) stability-indicating analytical methods applicable to regulatory submissions of small-molecule drug candidates. The discussion includes a comprehensive overview of the PPA-related regulatory and scientific landscape and common industry approaches to obtain PPA results, as well as the strengths and weaknesses of PDA-facilitated ultraviolet (UV) PPA and other PPA techniques.
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A Review of MOSH and MOAH Analysis in FoodAn overview of the analytical approaches proposed, from sample preparation to the final chromatographic determination, for the reliable risk assessment of mineral oil hydrocarbon (MOH) contaminants in food. The analysis of these contaminants in food is a challenging task and requires a comprehensive approach to tackle the cumbersome issues related to their determination.
