LC*GC

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COLUMNS

• LC TROUBLESHOOTING
  Effects of Flow Rate on UV Detection in Liquid Chromatography
  Dwight R. Stoll
  A deeper theoretical understanding of the relationship between peak area and flow rate will help analysts diagnose problems when using UV absorbance detection.
  
• PERSPECTIVES IN MODERN HPLC
  Chromatography Data Systems: Perspectives, Principles, and Trends
  Robert P. Mazzarese, Steven M. Bird, and Michael W. Dong
  This technical overview of chromatography data systems (CDS) looks at how CDS are designed, how they can be used most effectively, and what developments we can expect in the future.
  
• FOCUS ON FOOD ANALYSIS
  Studying Migration of Packaging Components into Food
  Laura Bush
  Perfecto Paseiro Losada and his group at the University of Santiago de Compostela, in Spain, describe their investigations into the kinetics of how packaging compounds migrate into foods and their studies to estimate dietary exposure.
  
• THE ESSENTIALS
  The Basics of HPLC Peptide Analysis
  Fundamentals aspects of using HPLC techniques for protein analysis are described as they relate to the analysis of post-translational modifications (PTMs) and glycoprofiles.
  

PEER-REVIEWED ARTICLES

• Determination of PAHs in Combustion-Related Samples via Multidimensional Chromatographic Methods
  Hugh V. Hayes, Walter B. Wilson, Lane C. Sander, Stephen A. Wise, and Andres D. Campiglia
  Gas chromatography–mass spectrometry (GC–MS), reversed-phase LC with stop-flow fluorescence (FL), and constant energy synchronous fluorescence spectroscopy (CESFS) are explored to determine PAH isomers in three combustion-related standard reference materials.
  
• Clinical Metabolomics: Expanding the Metabolome Coverage Using Advanced Analytical Techniques
  Rob Haselberg, Bob W.J. Pirok, Andrea F.G. Gargano, and Isabelle Kohler
  Clinical metabolomics requires analytical methods that provide both high resolution and high throughput. In this review, we assess the promise of a variety of techniques—including HILIC, SFC, multidimensional LC, ion-mobility mass spectrometry, and data-independent acquisition mass spectrometry methods—to meet those needs.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index

COLUMNS

• LC TROUBLESHOOTING
  Column Re-equilibration Following Gradient Elution: How Long is Long Enough? Part I: Reversed-phase and HILIC Separations of Small Molecules
  Dwight R. Stoll and Claudia Seidl
  Many users have questions about how long LC columns should be re-equilibrated following solvent gradient elution separations. Here we show satisfactory results with short re-equilibration periods, for both reversed-phase and HILIC separations.
  
• SAMPLE PREP PERSPECTIVES
  The (Mis)education of an Analyst
  Douglas E. Raynie
  Proper sample preparation is vital. We look at formal and informal training opportunities to educate chemists in the fundamentals of sample preparation skills.
  
• GC CONNECTIONS
  Online LC–GC: The Ultimate "GC Connection"
  Atsu Apedo and Nicholas H. Snow
  Multidimensional chromatography combining HPLC and GC, or LC–GC, sounds simple, but several factors complicate this combination, including solvent compatibility, separation time, and sample concentration.
  
• FOCUS ON BIOPHARMACEUTICAL ANALYSIS
  Utility of Hydrogen-Deuterium Exchange Together with Mass Spectrometry for Determining Higher Order Structures of Proteins: Comparisons Between Biosimilar and Innovator Biopharmaceuticals
  J. Auclair, A. Rathore, and I.S. Krull
  Hydrogen–deuterium exchange–mass spectrometry enables determination of higher order structures of biopharmaceuticals and direct comparisons between a biosimilar and its proprietary analog.
  
• FOCUS ON FOOD ANALYSIS
  Keeping Up with Evolving Challenges in Pesticide Analysis
  Laura Bush
  Jim Garvey of the Pesticide Control Laboratory in Ireland discusses the development of pesticide analysis methods with high-resolution accurate mass MS.
  
• THE ESSENTIALS
  Three Top HPLC Method Development Tips
  These three tips provide a clear starting point developing any HPLC method, to achieve optimum resolution in the minimum amount of time.
  

PEER-REVIEWED ARTICLE

• Chromatography Fundamentals, Part VIII: The Meaning and Significance of Chromatographic Resolution
  Howard G. Barth
  The effectiveness of a separation can be quantified by measuring the resolution. This article explains the factors influencing resolution and the equation for predicting the required number of theoretical plates to obtain a given esolution.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Calendar
• Ad Index

CURRENT TRENDS IN MASS SPCTROMETRY

ARTICLES

• Advancing Biopharmaceutical Analysis
  An introduction to this special issue by our guest editor.
• Monitoring of On-column Methionine Oxidation as Part of a System Suitability Test During UHPLC–MS/MS Peptide Mapping
  Björn Mautz, Vincent Larraillet, Maximiliane König, and Michael Mølhøj
  Long-term column use can lead to on-column methionine oxidation during LC–MS/MS peptide mapping of antibody-based biotherapeutics. Following the approach described here minimizes the risk of measuring oxidative artifacts, and helps generate high quality data to provide reliable quantitative information about product-related heterogeneities.
• Considerations and Advances in Developing Analytical Assays for Measuring Product-Related Variants in Bispecific Antibodies
  Ming Lei and Tao Chen
  Given the complexity of producing bispecific antibodies, suitable analytical methods to detect and measure the levels of undesired variants are essential. Here, a novel MS-based analytical method for variant detection is presented.
• Size-Exclusion Chromatography for the Analysis of Complex and Novel Biotherapeutic Products
  Jennifer Rea, David Fulchiron, Yun Lou, and Luda Darer
  Applications of size-exclusion chromatography (SEC) are presented for characterization and quality control of novel biotherapeutic products, including antibody–drug conjugates, hydrophobic proteins, and coformulations.
• Ferritin as a Natural Protein Scaffold: Building a Multivalent Ferritin–Fab Conjugate
  Whitney Shatz, Craig Blanchette, Patrick Holder, Robert F. Kelley, Remo Perozzo, and Yogeshvar N. Kalia
  In this study, a conjugation strategy for Fab–ferritin conjugates, used for drug delivery, was successfully optimized using LC–MS. Characterization of the resulting conjugates was performed using SEC-MALS-QELS.
• Utilizing Multidimensional LC–MS for Hydroxyl Radical Footprinting Analysis
  Julien Camperi, Arthur John Schick, Davy Guillarme, and Aaron T. Wecksler
  The potential of multidimensional online peptide mapping analysis as a strategy for improving a postlabeling workflow for protein–protein interactions is demonstrated using both hydroxy radical footprinting–mass spectrometry (HRF–MS) and LC–MS/MS.
• Development of a Size-Exclusion Chromatography Method to Characterize a Multimeric PEG–Protein Conjugate
  Lu Dai, Joseph Elich, and Fred Jacobson
  A simple and robust size-exclusion chromatography (SEC) method has been developed for characterizing a multimeric PEG–protein conjugate. A wide range of size variants of the conjugate, ranging from 50 kDa to >1000 kDa, can be resolved and quantitated.

COLUMNS

• COLUMN WATCH
  Highlights from the HPLC 2019 Symposium
  David S. Bell
  This “Column Watch” installment reports on highlights from the 48th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2019), held June 16 to 20 in Milan, Italy.
  
• LC TROUBLESHOOTING
  Minimizing Fluctuating Peptide Retention in 2D-LC: How to Address a Moving Target
  Patrik Petersson
  In this installment, tips, tricks, and suggestions are provided for best practices in reversed-phase separations, in both 1D and 2D LC, with gradient elution for minimum variations in retention time.
  
• PERSPECTIVES IN MODERN HPLC
  Ultraviolet Detectors: Perspectives, Principles, and Practices
  Michael W. Dong and Jedrzej Wysocki
  The authors provide a technical overview of the design and operating principles of variable wavelength and photodiode array detectors, and include historical perspectives and common practices in operation and maintenance.
  
• THE ESSENTIALS
  What a GC–MS Tune Report Can Tell You
  An essential tool for troubleshooting and tuning GC–MS instruments is the tune report; this article explains the meaning and uses of this report when combined with a tuning compound.
  

FEATURE ARTICLE

• Data Integrity Focus, Part IX: Understanding Data Integrity Metrics for Chromatography
  R.D. McDowall
  Here, we review the regulatory expectations of metrics for monitoring data integrity and discuss their practical implementation in a regulated chromatography laboratory.
  

PEER-REVIEWED ARTICLE

• Sampling: The Ghost in Front of the Laboratory Door
  Veronika R. Meyer
  How does one meet the most demanding part of an analysis—sampling? A typical example is soil, which presents a twofold problem for the analyst: first, the selection of the sites where the samples are taken, and second, the reduction of a sample (for example, 1 kg) to the analysis aliquot size (for example, 10 µL). This paper describes the details of sampling issues.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index

CURRENT TRENDS IN MASS SPCTROMETRY

ARTICLES

• Ionization Efficiency for Environmentally Relevant Compounds Using Atmospheric Pressure Photoionization Versus Electrospray Ionization
  Prakriya Shrestha, Katherine A. Maloof, Alayna Stephens, Clayton P. Donald, and Kevin R. Tucker
  In this study, atmospheric pressure photoionization (APPI) is compared to the default ionization method, electrospray ionization (ESI), for solution-phase samples. These mass spectrometry methods are compared and optimized relative to artificial wastewater for the detection and quantitation of pharmaceuticals frequently found as environmental contaminants.
  
• Recent Advances in Hyphenated Chromatography and Mass Spectrometry Techniques and Their Impact on Late-Stage Pharmaceutical Development
  Tony Bristow and Andrew Ray
  In late-stage pharmaceutical development a new generation of high?resolution mass spectrometers and ion mobility mass spectrometers operate as orthogonal separation techniques and have greatly increased the ability to resolve impurities and increase the level of analytical information gained from a single analysis.
  
• Quantitative Analysis of PFAS in Drinking Water Using Liquid Chromatography Tandem Mass Spectrometry
  Emily Parry and Tarun Anumol
  Per- and polyfluoroalkyl substances (PFAS) are found in firefighting foams and consumer products. They are ubiquitous in the environment and are an emerging human health concern. This work compares the 2009 and 2018 revised US Environmental Protection Agency (EPA) LC–MS/MS methods of analysis for PFAS in drinking water.
  
• Novel Methods Using Mass Spectrometry for Food Safety—From Contamination to Nutrition
  Ashley Sage, Jianru Stahl-Zeng, and Philip Taylor
  In the human food supply, public confidence is affected by contaminants and misreporting of nutritional information. This article highlights three events that required development of new mass spectrometry methods, including the detection of pesticides (such as fipronil and glyphosate), and the detection and quantification of fat-soluble vitamins.
  

DEPARTMENTS

• Products
• Application Notes

COLUMNS

• COLUMN WATCH
  Measurement of Interstitial Space Dispersion in Packed Bed Columns: Comparison of Superficially Porous and Fully Porous Particles
  Kim Vanderlinden, Ken Broeckhoven, and Gert Desmet
  Superficially porous particles have demonstrated separation efficiency gains compared to totally porous particles. The total pore blocking technique provides the purest possible measure of column packing quality. Here, we explain this technique and show what it has revealed.
  
• LC TROUBLESHOOTING
  Mind the Diluent: Effects of Sample Diluent on Analyte Recovery in Reversed-Phase and HILIC Separations
  Dwight R. Stoll and Anne E. Mack
  Carefully diluting a sample with weak solvent can mitigate the impact of sample solvent on peak shape in both reversed-phase and HILIC separations, but we need to understand how the choice of sample diluent can affect analyte recovery.
  
• GC CONNECTIONS
  Essential GC Accessories
  John V. Hinshaw
  Although manufacturers ship gas chromatographs with a collection of consumable parts and accessories, a number of other essential items should be on hand in every GC laboratory. What items are needed and how can they be used most effectively?
  
• THE ESSENTIALS
  An Introduction to Glycan Analysis
  Glycosylation is the most common monoclonal antibody (mAb) posttranslational modification. What is essential to know about it?
  

FEATURE ARTICLE

• Data Integrity Focus, Part VIII: What is Good Documentation Practice (GDocP)?
  R.D. McDowall
  Are EU GMP Chapter 4 and USP Chapter <1029> on Good Documentation Guidelines similar or complementary? Should we consider any other sources of advice?
  

PEER-REVIEWED ARTICLE

• Frontiers of Sampling: Design of High Surface Area Thin-Film Samplers for On-site Environmental Analysis
  Jonathan Grandy, Maryam Lashgari, Varoon Singh, and Janusz Pawliszyn
  In on-site environmental applications, representative sampling and proper replication are essential. For these reasons, recent work in thin-film solidphase microextraction has focused on the development of unique holders and customized samplers that are tailored for distinct sampling environments. Here, we explore the latest developments.
  

SPECIAL SECTION

• THE APPLICATION NOTEBOOK
  
  • Environmental
    
    • Separation of Nanoplastics and Determination of Their Surface Charge by Electrical Asymmetrical Flow Field-Flow Fractionation
      Postnova Analytics
      
    • Fractionation of Aliphatic and Aromatic Hydrocarbons in Petroleum Extracts
      Dr. Xiaoyan Wang, UCT, LLC
      
  • Food and Beverage
    
    • Separation of Selected Components of Ylang-Ylang Oil
      Adam L. Moore, PhD, Hamilton Company
      
    • Determination of Triphenylmethane Dyes from Aquaculture Samples
      Hans Rainer Wollseifen, Torsten Kretschmer, Johannes Brand, and Detlef Lambrecht, Macherey-Nagel GmbH & Co. KG
      
    • LC–MS/MS Analysis of Mycotoxins in Peanut Powder in 5.5 Min
      Restek Corporation
      
    • Shodex Rapid SUGAR Series: Fast Fermentation Monitoring and Sourdough Cultures
      Alex Schrum, Ron Benson, Marlon Rettis, and Leah Sullivan, Showa Denko America, Inc.
      
  • General
    
    • Analysis of Mycotoxins in Hemp and Hemp-Containing Edible Products
      Maria Ofitserova, PhD, and Sareeta Nerkar, PhD, Pickering Laboratories, Inc.
      
  • Medical/Biological
    
    • Complete Solution for TCA Cycle Organic Acid Analysis
      Robert Puryear and Piotr Macech, Imtakt USA,and Itaru Yazawa, Imtakt Japan
      
    • Transient Protein Self-Association Determined by SEC-MALS
      M. Burman and O. Schön, Glaxo-SmithKline
      
  • Pharmaceutical/Drug Discovery
    
    • Characterization of a Novel Antibody Drug Conjugate Mimic by Size-exclusion and Hydrophobic Interaction Chromatography
      Tosoh Bioscience
      
  • Polymer
    
    • Quantitative Analysis of Copolymers Using a Pyropobe
      Karen Sam, CDS Analytical
      

DEPARTMENTS

• Products
• Ad Index

COLUMNS

• LC TROUBLESHOOTING
  Pass the Salt: Evolution of Coupling Ion-Exchange Separations and Mass Spectrometry
  Dwight R. Stoll
  The high levels of non-volatile salts typically used in ion-exchange separations are incompatible with mass spectrometry. But the desire to directly couple these two powerful techniques has prompted researchers find solutions to this problem. Here are three approaches.
  
• SAMPLE PREP PERSPECTIVES
  Looking at the Past to Understand the Future: Soxhlet Extraction
  Douglas E. Raynie
  To better understand modern sample preparation techniques—such as ultrasound-assisted extraction, microwave-assisted extraction, and pressurized solvent extraction—we should look at the lessons these methods took from Soxhlet extraction.
  
• PERSPECTIVES IN MODERN HPLC
  HPLC Autosamplers: Perspectives, Principles, and Practices
  Carsten Paul, Frank Steiner, and Michael W. Dong
  We explain recent trends in HPLC autosampler design, provide recommendations for selecting one, and offer guidelines for operation and troubleshooting.
  
• THE ESSENTIALS
  The Importance of Tuning and Calibration in Liquid Chromatography–Mass Spectrometry (LC–MS)
  In LC–MS, the importance of tuning and calibrating the mass spectrometer cannot be overemphasized. There are six main aspects to address.
  

FEATURE

• Data Integrity Focus, Part VII: A Data Life Cycle for Chromatography
  R.D. McDowall
  Several regulatory data integrity guidance documents require that laboratories understand the data life cycle of their processes, but provide only vague definitions of what a data life cycle is. Here is a practical interpretation.
  

PEER-REVIEWED ARTICLE

• HILIC to the Rescue: Pharmaceutical Development Case Examples
  Jonathan G. Shackman
  HILIC has rapidly evolved into a practical technique. For analyzing highly polar compounds, HILIC can be far more straightforward than GC or reversed-phase LC with derivatization, and can lead to a simpler final method with robustness comparable to that of reversed-phase LC.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index

ANNUAL INDUSTRY TRENDS AND DIRECTORY ISSUE

• 2019 Salary Survey: Some Slight Gains and the Gender Gap Narrows
  
• Product Locator
  
• Products & Services
  
  • Liquid Chromatography
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  • Supercritical Fluid Chromatography
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  • Electrophoresis
  • Reagents, Solvents, Standards
  • Data Handling, Calibration
  • Chromatography Services
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  • General Scientific Equipment and Accessories
• Manufacturers Directory
  
• Product Profiles
  

COLUMNS

• COLUMN WATCH
  Hybrid Particle Columns: The First Twenty Years
  Thomas H. Walter
  We examine the evolution of hybrid particle columns, highlighting examples of separations enabled by this technology.
  
• LC TROUBLESHOOTING
  Mobile Phase Buffers in LC: Effect of Buffer Preparation Method on Retention Repeatability
  Dwight R. Stoll and Devin M. Makey
  Many analysts have strongly held beliefs about buffer preparation methods, but these positions are not always supported by experimental evidence.
  
• GC CONNECTIONS
  Temperature Programmed GC: Why Are All Those Peaks So Sharp?
  Nicholas H. Snow
  Temperature programming is used in most capillary GC separations, but many analysts lack a good understanding of the principles behind this approach.
  
• FOCUS ON ENVIRONMENTAL ANALYSIS
  Environmental Method Development: Key Challenges and Unmet Needs
  Michael MacRae
  The environmental analysis community sorely needs a system by which new and up-to-date methods are more easily developed, shared, and adopted.
  
• THE ESSENTIALS
  Electron Capture Detectors
  The fundamentals of electron capture detectors, explained.
  

PEER-REVIEWED ARTICLES

• The Determination of Trace Per- and Polyfluoroalkyl Substances and Their Precursors Migrated into Food Simulants from Food Contact Materials by LC–MS/MS and GC–MS/MS
  Dan Li, Zi-hao Zhang, Huai-ning Zhong, Lei Zhu, Jing-jing Pan, Jian-guo Zheng, Qin-bao Lin, and Hui Liu
  This integrated analytical approach combines HPLC–MS/MS and GC–MS/MS to detect 36 PFAS migrating into food simulants from packaging.
  
• Chromatography Fundamentals, Part VII: Influence of Peak Broadening on Detection Sensitivity, Solute Dilution, and Efficiency of Coupled Columns
  Howard G. Barth
  With these equations, you can predict how solute dilution will affect sensitivity.
  

FEATURE ARTICLE

• Under Pressure to Perform: Impact of UHPLC Technology on Pharmaceutical Research and Development
  Christopher J. Welch
  How has UHPLC has affected pharmaceutical research? The answer depends on your point of view.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Calendar
• Short Courses
• Ad Index

CURRENT TRENDS IN MASS SPECTROMETRY

• Articles
  • High-Throughput Experimentation: Where Does Mass Spectrometry Fit?
    Jessica Lin, Colin Masui, Raymond Lieu, and Kelly Zhang
    In the pharmaceutical industry, the use of mass spectrometry in high-throughput experimentation (HTE) has increased, thanks to the technique’s speed, sensitivity, and selectivity. We systematically evaluate the applicability of multiple MS techniques for different types of HTE samples and purposes, reviewing the pros and cons, and provide practical recommendations, Illustrated by application case studies.
    
  • Laser Thermal Desorption and GC×GC for Harsh Environment and Planetary Mass Spectrometry
    Mark Libardoni and Ryan Blase
    The development of analytical instrumentation for harsh terrestrial environments and outer planet space exploration exponentially increases instrument requirements—for features such as robustness, autonomous operation, and speed—and poses unique system integration challenges. Here, we explore the use of laser thermal desorption coupled to comprehensive two-dimensional gas chromatography (LTD-GC×GC) for use with a compact, high-resolution mass spectrometer for challenging applications.
    
  • A Brief Review of Recent Advances in Isomeric N- and O-Glycomics
    Yehia Mechref, Wenjing Peng, and Yifan Huang
    Glycan isomer expressions have not been well studied, due to inefficient separation and structural identification techniques. Fortunately, with the development of novel separation techniques and liquid chromatography–mass spectrometry (LC–MS) based glycan isomer identification strategies, new efforts have been made to investigate the glycan isomers in various diseases. Here, we review the recent advances of several isomeric separation techniques for both N- and O-linked glycans.
    
• Departments
  • ASMS Product Profiles
  • Application Notes

COLUMNS

• COLUMN WATCH
  Making the Most of Size-Exclusion Bioseparations Using Sub-2-µm Column Technology
  Te-Wei Chu, Veronica Qin, Andrew Coffey, Eric Lyster, Wu Chen, and Gregory Staples
  With SEC, special care is required to achieve in practice the chromatographic efficiency that is expected from theory.
  
• LC TROUBLESHOOTING
  Mixing and Mixers in Liquid Chromatography, Part III: Solutions for Problems with Sample Diluents
  Zachary Breitbach, Corianne Randstrom, Jean Chang, Michael Lesslie, Gregory Webster, and Dwight R. Stoll
  An in-line mixer between the sample injector and column may resolve problems with peak shape caused during sample dilution.
  
• PERSPECTIVES IN MODERN HPLC
  Modern HPLC Pumps: Perspectives, Principles, and Practices
  Konstantin Shoykhet, Ken Broeckhoven, and Michael W. Dong
  Gaining a solid understanding of how HPLC instrumentation works will help you achieve success in the analytical laboratory. This four-part series is here to guide you, starting with pumps.
  
• FOCUS ON BIOPHARMACEUTICAL ANALYSIS
  Practical Considerations of Capillary Electrophoresis–Mass Spectrometry for Analysis of Biotherapeutics
  Anurag S. Rathore, Ramesh Kumar, and Ira S. Krull
  Coupling CE with MS presents some challenges. Here, we discuss the advantages of CE–MS over LC–MS, and the parameters that are important to obtain a stable CE–MS profile.
  
• THE ESSENTIALS
  Solving Recovery Problems in Solid-Phase Extraction
  Improved practices in chemistry selection and sample processing may resolve recovery issues related to target analytes or internal standards.
  

FEATURE ARTICLES

• Data Integrity Focus, Part VI: Who Is Looking Over Your Shoulder? Quality Oversight for Data Integrity
  R.D. McDowall
  What are the roles and responsibilities of quality assurance staff for ensuring data integrity in an organization?
  
• Evaluation of Achiral Stationary Phases for Gradient Screening with Supercritical Fluid Chromatography
  Raffeal Bennett, Matthew Przybyciel, Erik L. Regalado, and Mirlinda Biba
  Unlike reversed-phase liquid chromatography, SFC lacks a universal stationary phase. Thus, it is important to re-evaluate the default column screening library used with SFC. In this study, three uncommon achiral SFC columns were investigated and compared to three popular stationary phases.
  

THE APPLICATION NOTEBOOK

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index

Recent Developments in HPLC and UHPLC

• Looking To The Future
  Gert Desmet
  An introduction to this special issue from the guest editor.
  
• Vacuum-Jacketed Columns: Maximum Efficiency, Easy Deployment Without Oven, and Improved LC–MS Performance
  Fabrice Gritti
  The design of a user-friendly vacuum-jacketed column (VJC) is described for improved LC–MS performance, which does not require a large vacuum chamber with multiple vacuum pumps. Using this configuration, the experimental peak capacities measured for a 2.1 mm × 100 mm column packed with sub-2-µm particles and placed in the VJC-MS probe are doubled with respect to standard LC–MS systems.
  
• Recycle Reversed-Phase Liquid Chromatography to Achieve Separations Based on One H/D Substitution on Aromatic Hydrocarbons
  Kazuhiro Kimata, Tsunehisa Hirose, Eisuke Kanao, Takuya Kubo, Koji Otsuka, Ken Hosoya, Kohei Yoshikawa, Eiichiro Fukusaki, and Nobuo Tanaka
  Ultrahigh efficiency separations based on the presence of one deuterium in benzene, toluene, and naphthalene were achieved by recycle chromatography using C18 silica columns. The discrimination mechanism of H/D isotopic species is discussed based on the dispersion interactions of a CH/CD group of the solute with the stationary phase as well as the mobile phase.
  
• Progress in Peak Processing
  M. Farooq Wahab, Garrett Hellinghausen, and Daniel W. Armstrong
  The advantages and limitations of several recently introduced mathematical procedures for enhancing peak resolution in liquid chromatography (LC) are described. Despite advanced separation technologies and extensive knowledge in method development, peak overlap is still commonly observed. This article gives a brief overview of the advantages and limitations of recently introduced mathematical procedures for enhancing resolution.
  
• Optimization of MS-Compatible Mobile Phases for IEX Separation of Monoclonal Antibodies
  Evelin Farsang, Amarande Murisier, Krisztián Horváth, Olivier Colas, Alain Beck, Davy Guillarme, and Szabolcs Fekete
  The impact of ionic strength, buffer capacity, and pH-response on the retention behavior and peak shape of mAb species characterization is evaluated for IEX-MS. The aim of the present study was to understand the impact of ionic strength, buffer capacity, and pH-response on the retention behavior and peak shape of mAb species.
  

COLUMNS

• LC TROUBLESHOOTING
  Methods from Mars? Coping with Chromatographic Legacies
  Dwight R. Stoll and Tony Taylor
  Legacy LC methods seem like they come from a different planet. This month, we look at which conditions to keep, and which ones to let go.
  
• SAMPLE PREP PERSPECTIVES
  New Sample Preparation Products and Accessories
  Douglas E. Raynie
  Our annual report of sample preparation instrumentation, supplies, and accessories for gas and liquid chromatography
  
• GC CONNECTIONS
  New Gas Chromatography Products for 2018–2019
  John V. Hinshaw
  Our annual review of new developments in the field of gas chromatography, as seen at Pittcon and other venues
  
• THE ESSENTIALS
  Modern Mobile Phase Design for HPLC
  In recent years, there has been a paradigm change in the way we approach mobile phase design for high performance liquid chromatography (HPLC). What are the trends?
  

FEATURE ARTICLES

• Data Integrity Focus, Part V: How Can USP <1058> Help Data Integrity?
  R.D. McDowall
  USP chapter <1058> can help ensure data integrity of a chromatography data system. Here’s how.
  
• Statistics for Analysts Who Hate Statistics, Part VIII: Decision Trees
  Caroline West
  Decision trees offer great visuals to observe complex data sets and to classify data according to simple decision rules.
  

PEER-REVIEWED ARTICLE

• Development of Fully Automated Bubble-in-Drop Microextraction–Gas Chromatography–Mass Spectrometry of Organochlorine Pesticides in Environmental Waters
  Claire A. Taylor, Hui Min Lee, and Hian Kee Lee
  By optimizing and fully automating the bubble-in-drop microextraction process, this sample preparation technique, combined with gas chromatography–mass spectrometry (GC–MS) analysis, provides high precision and good figures of merit, as shown for selected organochlorine pesticides in the analysis of tap water and reservoir water samples.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index
• Calendar
• Short Courses

CURRENT TRENDS IN MASS SPECTROMETRY

• Articles
  • Determination of the Relative Prevalence of Lurasidone Metabolites in Urine Using Untargeted HRMS
    Erin C. Strickland, Jeffrey R. Enders, and Gregory L. McIntire
    For lurasidone treatment adherence testing, an untargeted high-resolution mass spectrometry method was employed, using known positive human urine samples to identify the lurasidone metabolites and their relative abundance in urine.
    
  • Quantitation and Nontargeted Identification of Pesticides in Spinach Extract with GC×GC–TOF-MS
    Todd Richards and Joseph Binkley
    In this study of pesticides in spinach extract, the use of GC×GC–TOF-MS is demonstrated as a methodology to overcome matrix interferences and quickly quantify suspected contaminants. The approach also allows nontargeted analysis using a single sample injection.
    
  • High-Throughput Structure-Based Profiling and Annotation of Flavonoids
    Simon Cubbon
    A novel mass spectrometry-based flavonoid profiling workflow is applied to characterize and structurally annotate a large number of unknown flavonoids in fruit juice and vegetable juice samples.
    
• Departments
  • Products
  • Ad Index

COLUMNS

• COLUMN WATCH
  New Liquid Chromatography Columns and Accessories for 2019
  David S. Bell
  Our annual review of new liquid chromatography columns and accessories.
  
• LC TROUBLESHOOTING
  Reversed-Phase Liquid Chromatography and Water, Part II: Re-equilibration of the Stationary Phase Following Gradient Elution
  Dwight R. Stoll
  Re-equilibrating a reversed-phase stationary phase following aqueous gradient elution can be achieved much faster than you think.
  
• PERSPECTIVES IN MODERN HPLC
  New HPLC Systems and Related Products Introduced in 2018–2019: A Brief Review
  Michael W. Dong
  New HPLC and MS systems: A review of instrumentation trends and the current market along with new instruments, modules, chromatography data systems, and related software.
  
• FOCUS ON ENVIRONMENTAL ANALYSIS
  Trends in Water Analysis
  Laura Bush
  In this interview, Thomas Letzel of the Technical University of Munich considers the current state of water analysis, looking at recommended techniques, thegrowth of nontargeted screening, and multi-disciplinary collaboration.
  
• THE ESSENTIALS
  Electron Ionization in GC–MS
  We provide a succinct explanation of electron ionization for GC–MS and illustrate the fundamentals of ion formation.
  

FEATURE

• Data Integrity Focus, Part IV: Are Raw Data and Complete Data the Same?
  R.D. McDowall
  The meaning of the terms raw data and complete data are explored. One term is from EU GMPs and the other is from US GMPs. Do they mean the same thing?
  

PEER-REVIEWED ARTICLE

• Chromatography Fundamentals, Part VI: The Gaussian Distribution and Moment Analysis
  Howard G. Barth
  How well do Gaussian-shaped profiles represent injected solute peaks after they are eluted through a chromatographic column? This question is explored along with a discussion of moment analysis for determining retention time, variance, and shapes of peaks.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index
• Calendar

RECENT DEVELOPMENTS IN SAMPLE PREPARATION

• Articles
  • Advancing Chromatographic Analysis Using Selective and Robust Sample Preparation
    Jared L. Anderson
    The field of sample preparation is undergoing revolutionary change, largely governed by the need for miniaturization while maintaining high selectivity and high analyte enrichment. How up-to-date are you in the advances of sample preparation for chromatographic analysis?
    
  • Dispersive Miniaturized Solid-Phase Extraction Using the CIM-81 Metal-Organic Framework and Gas Chromatography–Mass Spectrometry to Determine Personal Care Products in Waters
    Providencia González-Hernández, Ana B. Lago, Jorge Pasán, Juan H. Ayala, Ana M. Afonso, and Verónica Pino
    In this study, the analysis of contaminants found in environmental waters and originating from personal care products is addressed using metalorganic frameworks (MOFs) in combination with liquid chromatography (LC). This work expands the use of MOFs from gas chromatography to LC and also meets the requirements of green analytical chemistry.
    
  • Solid-Phase Microextraction Combined with Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography for Screening Leachables in the Pharmaceutical Industry
    Juliana Crucello, Andre Cunha Paiva, and Leandro W. Hantao
    A simple, fully-automated method is proposed to analyze extractables and leachables—compounds that are released from packing materials into drugs during storage—using SPME-GC×GC–MS. This method avoids the use of sample preparation solvents and reduces sample handling, and is ideal for routine use in quality control.
    
  • Nanomaterials Have Come to Stay: An Overview of their Use as Sorbents in Sample Preparation
    Javier González-Sálamo, Diana Angélica Varela-Martínez, Carlos Cairós, Miguel Ángel González-Curbelo, and Javier Hernández-Borges
    Nanomaterials are extremely useful as sorbents for sample preparation, because of their varied morphologies, high surface area, surface-tovolume ratio, porosity, and ability to interact with samples in a variety of ways. Here, we review how nanomaterials are being used in a variety of sample preparation techniques, such as dispersive solid-phase extraction (dSPE), solid-phase microextraction, stir-bar sorptive extraction, and matrix solid-phase dispersion.
    
  • Exploring the Efficiency of Various Extraction Approaches for Determination of Crude (4-methylcyclohexyl)methanol (MCHM) Constituents in Environmental Samples
    Ronald V. Emmons, Amila M. Devasurendra, Nipunika H. Godage, and Emanuela Gionfriddo
    Crude (4-methylcyclohexyl)methanol (MCHM) is a chemical contaminant that must be monitored in fresh water environments, because of significant health risks to surrounding human populations. A new method for MCHM analysis was developed using solid-phase microextraction (SPME) and thin film microextraction (TFME) combined with GC–MS. Both methods achieved limits of quantitation lower than standard methods using SPE.
    
  • “Truly Natural”: Fully Automated Stir-Bar Sorptive Extraction with Enantioselective GC–MS Quantitation of Chiral Markers of Peach Aroma
    Cecilia Cagliero, Alessandro Guglielmetti, Chiara Cordero, Erica Liberto, Arianna Marengo, Barbara Sgorbini, Patrizia Rubiolo, and Carlo Bicchi
    A simple, automated, and fast method to quantify complex odorants in foods is described using stir-bar sorptive extraction (SBSE) combined with fast enantioselective GC–MS analysis. The total analytical method takes only 30 minutes and does not require any sample pretreatment.
    

COLUMNS

• COLUMN WATCH
  Perspectives on the Adoption and Utility of 1.0-mm Internal Diameter Liquid Chromatography Columns
  David S. Bell
  We assess the advantages and disadvantages of 1.0-mm diameter columns.
  
• LC TROUBLESHOOTING
  Looking for New Selectivity in Reversed-Phase Liquid Chromatography? A View of the Selectivity Landscape Over the Past Two Years
  Dwight R. Stoll
  How many new columns truly offer new selectivity?
  
• SAMPLE PREP PERSPECTIVES
  Recent Advances in Solid-Phase Microextraction, Part II: Bio-SPME
  Douglas E. Raynie
  Bioanalysis with SPME has advanced greatly over the past decade.
  

PEER-REVIEWED ARTICLES

• Data Integrity Focus, Part III: What Is the Problem with Hybrid Systems?
  R.D. McDowall
  A hybrid system is the worst possible choice for managing your regulated data.
  
• Instrument Considerations in the Transfer of Chromatographic Methods, Part III: Aligning Performance of Modules
  Thomas E. Wheat
  In method transfer, carefully aligning the modules of the two systems is essential.
  
• Determination of Diclofenac in Water Samples from Wastewater Treatment Plants by Large Volume Injection-Gas Chromatography–Mass Spectrometry
  Álvaro Aragón, Rosa M. Toledano, Ana Vázquez, Jesús Villén, and José M. Cortés
  A new method to analyze low concentrations of the drug diclofenac in wastewater.
  
• Pressure Tuning: Increasing the Flexibility of Comprehensive Two-Dimensional Gas Chromatography
  Mohammed Sharif Khan and Philip John Marriott
  Pressure tuning makes it easy to change the orthogonality in the 2D space.
  

THE LCGC AWARDS: INTERVIEWS

• The 2019 Lifetime Achievement in Chromatography Award: Professor Milos V. Novotny on His Chromatographic Journey
  Jerome Workman, Jr.
  Prof. Novotny discusses the joys of mentoring and the future of separation science.
  
• The 2019 Emerging Leader in Chromatography Award: Ken Broeckhoven on Investigating the Performance Limits of HPLC Separations
  Jerome Workman, Jr.
  Ken Broeckhoven explains his pursuit of ever higher performance in HPLC.
  

DEPARTMENTS

• Peaks of Interest
• ISCC and GCxGC Preview: Honey I Shrunk the HPLC.
• Calendar
• Short Courses
• Products & Resources
• Ad Index
• The Essentials

Current Trends in MASS Spectrometry

• Articles
  • Plant Metabolomic Workflows Using Reversed-Phase LC and HILIC with ESI-TOF-MS
    Rofida Wahman, Johanna Grassmann, Peter Schröder, and Thomas Letzel
    In plant metabolomics, molecular fingerprints and additional molecular descriptors can be identified using recent developments in polarity-extended separations with serial coupling of reversed-phase LC and HILIC combined with ESI-TOF-MS.
    
  • A Robust and Sensitive Method for Detecting Glyphosate and Other Polar Pesticides in Food and Water: Multiple Analytes in a Single Injection without Derivatization
    Wim Broer, Ugo Chiuminato, Jianru Stahl-Zeng, Daniel McMillan, and Phil Taylor
    A new high-throughput LC–MS/MS method meets the challenge of eliminating matrix effects for monitoring, with high specificity, polar organic pesticides such as glyphosate in food and water, while meeting targeted limits of detection.
    
  • GC×GC–MS for Forensic Analysis
    Candice M. Bridge, Mark Maric, and Kaitlin Jones
    Forensic scientists often encounter highly complex analytical problems related to crime scenes that would benefit from the capabilities of GC×GC–MS. However, this technique has not been fully explored to help benefit forensic laboratories.
    
  • The Benefits of Data-Independent Acquisition in Metabolomics
    Alasdair Matheson
    Data-independent acquisition (DIA) makes it possible to re-interrogate data from earlier analyses to determine if new compounds have appeared in a sample previously analyzed. In this interview, Craig Wheelock of the Karolinska Institute discusses the use of DIA in metabolomics.
    
• Departments
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COLUMNS

• LC TROUBLESHOOTING
  Reversed-Phase Liquid Chromatography and Water, Part I: How Much is Too Much?
  Dwight R. Stoll
  In reversed-phase separations, retention generally increases as the fraction of water in the eluent increases. When we encounter situations where retention is too low for an analyte of interest, we tend to use eluents with higher and higher levels of water. But how much water is too much?
  
• GC CONNECTIONS
  GCxGC: From Research to Routine
  Nicholas H. Snow
  Two-dimensional gas chromatography (GCxGC) is becoming the technique of choice for analysis of highly complex samples such as petroleum, pharmaceuticals, biological materials, food, flavors, and fragrances. Here, we explain how GCxGC works and provide examples that illustrate its advantages.
  
• THE ESSENTIALS
  Optimizing Sensitivity in GC–FID Analysis
  It is often possible to achieve better sensitivity and lower limits of detection and quantitation using standard gas chromatography instrumentation. Paying attention to fundamental variables—like sample solvent, initial oven temperature hold, carrier gas operating mode, and thermal gradients— can lead to much improved method performance.
  

FEATURE ARTICLES

• The 2019 LCGC Awards
  Jerome Workman Jr.
  The contributions of Milos V. Novotny and Ken Broeckhoven, the winners of the 2019 LCGC Lifetime Achievement and Emerging Leader in Chromatography Awards, are presented.
  
• Data Integrity Focus, Part II: Using Data Process Mapping to Identify Integrity Gaps
  R.D. McDowall
  Data integrity is paramount when working in a regulated environment. Data process mapping is an excellent way to identify and mitigate data gaps and record vulnerabilities in a chromatographic process. This approach is simple and practical.
  

THE APPLICATION NOTEBOOK

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Ad Index

COLUMNS

• SAMPLE PREP PERSPECTIVES
  Is Headspace Sampling Quantitative?
  Douglas E. Raynie
  Whether or not headspace sampling is quantitative depends on the information gleaned from the analysis.
  
• LC TROUBLESHOOTING
  What’s Trending in LC Troubleshooting?
  Dwight R. Stoll
  We look at problems in LC that can be traced to contaminated solvents or reagents, and how sample solvent effects can lead to poor performance in HILIC.
  
• GC CONNECTIONS
  Stopping GC and GC–MS Problems Before They Start
  Nicholas H. Snow
  By taking simple proactive troubleshooting steps, GC users can ensure that instruments will operate correctly over time, thus avoiding workflow disruptions.
  
• FOCUS ON BIOPHARMACEUTICAL ANALYSIS
  Methods and Purposes for Determining Higher Order Structures of Biopharmaceuticals
  J. Auclair, A. Rathore, and Ira S. Krull
  Determining the higher order structure of a protein pharmaceutical is important. Here, we review the approaches for HOS determination that are currently receiving the most attention in the literature and at scientific meetings.
  
• THE ESSENTIALS
  Essential Theory of HPLC
  The elution mechanisms for gradient and isocratic HPLC are fundamentally different from each other. Here is what you should understand about both.
  

FEATURE ARTICLE

• Data Integrity Focus, Part 1: Understanding the Scope of Data Integrity
  R.D. McDowall
  There are many factors to consider in a data integrity and governance program. Fortunately, a simple diagram can help us understand what needs to be covered.
  

PEER-REVIEWED ARTICLE

• Suspect Screening of Chemicals in Food Packaging Plastic Film by Comprehensive Two-Dimensional Gas Chromatography Coupled to Time-of-Flight Mass Spectrometry
  Yelena Sapozhnikova and Eunha Hoh
  The occurrence of additives like plasticizers in plastic food packaging has been documented, but information on their potential migration into foods is limited. In this pilot study, 2D GC–MS was used to identify chemicals extracted from a common stretch plastic film with a series of organic solvents. In total, 91 compounds were tentatively identified, including five PCBs.
  

DEPARTMENTS

• Peaks of Interest
• Products & Resources
• Calendar
• Short Courses
• Ad Index