LC*GC

December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1995 - 1996

COLUMNS

• SAMPLE PREP PERSPECTIVES
  Practical Aspects of Solvent Extraction
  Ronald E. Majors
  Columnist Ron Majors discusses some of the practical considerations in the successful application of the popular yet age-old technique of solvent extraction (also known as liquid-liquid extraction, or LLE). After a brief review of the basics, guidelines on the selection of the appropriate extraction solvents, and how to use acid-base equilibria to ensure efficient extractions of ionic and ionizable compounds are examined.
  
• LC TROUBLESHOOTING
  LC Pumps
  John W. Dolan
  This month's "LC Troubleshooting" installment will take a look at the design of these durable pumps and also examine some of the potential weaknesses and how to overcome them.
  
• MS - THE PRACTICAL ART
  A Mass Spectrometry Primer, Part III
  Michael P. Balogh
  Part III concludes the print version of our three-part series, "A Mass Spectrometry Primer," with the glossary to follow in a fourth and final installment. To recap the basis for undertaking this work, technological changes that affect our knowledge, in terms of its depth and our speed of accessing it, spur a couple of observations about print media versus electronic.
  
• VALIDATION VIEWPOINT
  A Quality-by-Design Methodology for Rapid LC Method Development, Part I
  Joseph Turpin, Patrick H. Lukulay, and Richard Verseput
  This installment of "Validation Viewpoint" describes how statistically rigorous quality-by-design (QbD) principles can be put into practice to accelerate each phase of liquid chromatography (LC) instrument method development. Here, in Part I, the authors examine the current approaches to column screening in terms of design space coverage - a key element of process knowledge.
  

EDITORIAL INDEX

• 2008 Index of Authors and Subjects
  

DEPARTMENTS

• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• SAMPLE PREP PERSPECTIVES
  The Role of Polymers in Solid-Phase Extraction and Sample Preparation
  Ronald E. Majors
  This installment of SPP will compare and contrast the various types of polymeric and non-polymeric sorbents. The major advantages of polymeric sorbents will be discussed, and some applications will illustrate the versatility of polymeric SPE materials.
  
• LC TROUBLESHOOTING
  Extracolumn Effects
  John W. Dolan
  All the buzz lately about liquid chromatography (LC) columns packed with particles smaller than 3 mm often comes with warnings about extracolumn effects. For this month's LC Troubleshooting installment we will take a look at what these effects are and how they might influence the separations obtained from your LC system.
  
• GC CONNECTIONS
  Frequently Asked Questions about Hydrogen Carrier Gas
  John V. Hinshaw
  Chromatographers are choosing hydrogen carrier gas more often for their applications for reasons of performance and, in the face of increasing helium prices, for cost reasons as well. John Hinshaw addresses some of the more frequently asked questions he encounters about hydrogen as carrier gas.
  
• VALIDATION VIEWPOINT
  Analytical Method Validation in Proteomics and Peptidomics Studies
  Ira Krull and P.T. Kissinger
  While the Validation Viewpoint column has focused on conventional and recombinant pharmaceutical products, and at times, bioanalytical methods, we have just begun to think about method validation as it relates to -omics type studies.
  

ARTICLE

• Biomonitoring: Polybrominated Diphenyl Ethers and Polybrominated Biphenyls Using Capillary GC with Electron-Capture Negative Ion Mass Selective Detection
  Paul R. Loconto
  A selective and highly sensitive capillary gas chromatographic-mass spectrometric approach has been developed for the detection of PBDEs and PBBs that utilizes dissociative resonance electron capture and selected ion monitoring.
  

DEPARTMENTS

• Peaks of Interest
• Products
• Literature
• Calendar
• Short Courses
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Shape Selectivity in Reversed-Phase Liquid Chromatography
  Catherine A. Rimmer, Katrice A. Lippa, and Lane C. Sander
  A variety of chromatographic sorbents are commercially available for reversed-phase liquid chromatography (RPLC) and while many of these columns are nominally similar, in practice the columns may provide significantly different separations.
  
• LC TROUBLESHOOTING
  Drip, Drip, Drip . . .
  John W. Dolan
  This LC Troubleshooting installment marks the beginning of the 26th year that John Dolan has written this column. Over that time, changes in instrument design, and especially column technology, have occurred that have made liquid chromatography (LC) an easy-to-use and reliable process. Some problems, however, have not gone away and probably never will. Leaks fall in this category.
  
• MS - THE PRACTICAL ART
  A Mass Spectrometry Primer, Part II
  Michael P. Balogh
  In the second part of this series, Michael Balogh answers more questions about about mass spectrometers, their use and capabilities, and includes further links to more detailed reading in readily available articles written for the nonspecialist.
  
• HISTORY OF CHROMATOGRAPHY
  Kurt Grob - One of the Fathers of Capillary GC
  Koni Grob
  In this month's installment, Kurt Grob's life and achievements are described by someone who knew him like few other people did: his son, Koni Grob.
  

ARTICLE

• Review and Optimization of Linearity and Precision in Quantitative HPLC-ELSD with Chemometrics
  Wayne O. Aruda, Steven Walfish, and Ira S. Krull
  HPLC with ELSD continues to grow in popularity as a "quasiuniversal" detector. Improvements in ELSD instrument design, including low temperature evaporation, have recently been commercialized, and other potential improvements can further enhance the sensitivity of ELSD. These are explored here.
  

DEPARTMENTS

• From the Editor
• Peaks of Interest
• Products
• Literature
• Calendar
• Short Courses
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Highlights of HPLC 2008: Part II
  Ronald E. Majors
  Ron Majors continues his summary of the technical highlights of HPLC 2008, discussing more hot topics from the show.
  
• LC TROUBLESHOOTING
  Odds and Ends from the Inbox
  John W. Dolan
  John Dolan regularly receives e-mails from readers with a wide variety of questions. As he cleans out his inbox, he chooses a few to share.
  
• GC CONNECTIONS
  A Shock to the System, Part II
  John V. Hinshaw
  John Hinshaw concludes his two-part series on electrical issues in the laboratory.
  
• DIRECTIONS IN DISCOVERY
  Isoelectric Prefractionation for Proteomics
  Tim Wehr
  A number of commercial in-solution, off-gel, and in-gel IEF fractionation systems are described in this month's column.
  

ARTICLES

• Improving the Confidence of Unknown Compound Identification by First Responder Mobile GC-MS Laboratories in Time-Critical Environmental and Homeland Security Incidents
  Jianping Chen, Ming Gu, Yongdong Wang, and Don Kuehl
  A novel method that significantly improves the accuracy and reliability of "unknown" compound identification for volatile organic compounds by GC-MS is described.
  
• Stability of Formic Acid in Methanol Solutions and the Implications for Use in LC-MS Gradient Elution Analysis
  Karel A.J. Snoble, Neal M. Fox, Sandra M. Lorenz, Anthony R. Kemperman, and J.T. Przybytek
  Dilute formic acid solutions in methyl alcohol are found to decline in acid content with time, the extent of the decline depending upon the initial amount of water present in these solutions. The effect of the formic acid concentration change upon the separation of peptides using HPLC is briefly examined as well.
  

DEPARTMENTS

• Peaks of Interest
• Products
• Literature
• Calendar
• Short Courses
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Highlights of HPLC 2008: Part I
  Ronald E. Majors
  HPLC 2008 was held in Baltimore in May. Columnist Ron Majors covers the highlights of this major symposium, held in the U.S. every two years. In this month's "Column Watch" he summarizes the plenary lectures and discusses trends in technologies and applications.
  
• LC TROUBLESHOOTING
  Column Care
  John W. Dolan
  After returning from Israel, John Dolan dedicates this month's LC Troubleshooting discussion to three problems that know no international boundaries: how to condition a new column, the effect of washing a column with water, and recommendations on cleaning a column after it has been used to analyze samples.
  
• MS - THE PRACTICAL ART
  A Mass Spectrometry Primer: Part I
  Michael P. Balogh
  Michael Balogh begins a three-part overview series, answering questions about about mass spectrometers, their use and capabilities, and including links to more detailed further reading in readily available articles written for the nonspecialist. Terminology and common usage is defined as well.
  
• VALIDATION VIEWPOINT
  Linear Thinking in a Nonlinear World
  Candice B. Kissinger and Peter T. Kissinger
  A very useful construct in engineering and analytical chemistry is the concept of a time-invariant linear system. The properties of the system (as for a mathematical function) are defined by a relationship between the response and the excitation, and this is discussed by the guest coumnists here.
  

ARTICLE

• Chemometrical Experimental Design-Based Optimization Studies in Capillary Electrophoresis Applications
  Ruthy Montes, Froseen Dahdouh, Toni Ann Riveros, Grady Hanrahan, and Frank A. Gomez
  A synopsis of the authors' work detailing the use of chemometric response surface methodology (RSM) in two capillary electrophoresis (CE) studies is described. They demonstrate the usefulness of employing RSM to specific CE applications, thereby proving the utility of chemometrics design in experimental optimization.
  

DEPARTMENTS

• Peaks of Interest
• From the Editor
• Products
• Literature
• Calendar
• Short Courses
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  LCxLC: Comprehensive Two-Dimensional Liquid Chromatography
  Peter Schoenmakers
  Guest Editor Peter Schoenmakers provides an introduction to LCxLC, and then goes on to talk about peak capacity, sample dimensionality, phase orthogonality, and some of the successes of the technique and the obstacles yet to be overcome.
  
• LC TROUBLESHOOTING
  Peak Shape Problems
  John W. Dolan
  Most of us are quite familiar with tailing peaks in LC separations. But what about those chromatograms in which all the peaks have severely tailing peaks, or split or doubled peaks? Then there are peaks that front badly - a rare event for most workers - but common under certain conditions. This month's "LC Troubleshooting" column will consider these last two problem areas.
  
• GC CONNECTIONS
  A Shock to the System
  John V. Hinshaw
  This month in "GC Connections," in the first of a two-part series, John Hinshaw relates what happens when high-voltage spikes attack modern electronic equipment, what to do when they occur, and how to set up equipment to minimize damage and loss of data.
  
• HISTORY OF CHROMATOGRAPHY
  From Academician to Entrepreneur - A Convoluted Trek
  Walt Jennings
  Walt Jennings briefly sketches a path, occasionally humorous, occasionally somber, from the time of his Ph.D. candidacy in 1953 to the present day.
  

ARTICLE

• A Hydrophilic Interaction Chromatography Method for the Purity Analysis of Cytosine
  Mark Strege, Charles Durant, John Boettinger, and Michael Fogarty
  The authors meet the need for a method for the determination of cytosine purity by developing a hydrophilic interaction chromatography (HILIC) method with demonstrated advantages in comparison to other separation techniques.
  

DEPARTMENTS

• Peaks of Interest
• From the Editor
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Comparison Techniques For HPLC Column Performance
  Gert Desmet
  Guest Columnist and LCGC Emerging Leader award recipient Gert Desmet considers the different methods that can be used to compare the performance of liquid chromatography columns and to assess the advantage of the high pressures and high temperatures at which some of them can be used.
  
• LC TROUBLESHOOTING
  Check Valves and Acetonitrile
  John W. Dolan
  John Dolan has discovered that check-valve problems have jumped to the top of the list with LC users. He takes a look at them here.
  
• MS - THE PRACTICAL ART
  Determining Health Hazards: A Look into the EPA Practice
  Michael P. Balogh
  The matter of perfluorinated compounds became a focus of the EPA some eight years ago. These compounds have become the source of legitimate concern: their resistance to atmospheric and biological degradation and an ability to persist in the environment may also prove bioaccumulative and toxic.
  
• DIRECTIONS IN DISCOVERY
  Enriching the Phosphoproteome
  Tim Wehr
  Protein phosphorylation plays a central role in the regulation of cellular functions and processes, and characterization of the phosphoproteome is key to our understanding of these processes. However, analysis of protein phosphorylation requires enrichment of phosphoproteins. This installment of "Directions in Discovery" will review current phosphorylation enrichment techniques with a focus on new developments.
  

ARTICLE

• Inside the Personalized Medicine Toolbox: GC3GC-Mass Spectrometry for High-Throughput Profiling of the Human Plasma Metabolome
  Adam W. Culbertson, W. Brent Williams, Andrew G. Mckee, Xiang Zhang, Keith L. March, Stephen Naylor, and Stephen J. Valentine
  The authors present results that suggest that high-throughput, high-coverage profiling capabilities, such as those afforded by GC3GC-TOF-MS, can impact the development of personalized medicine.
  

DEPARTMENTS

• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• SAMPLE PREP PERSPECTIVES
  Dynamic Extraction: A High-Speed, High-Capacity Purification Process That is Rapidly Scalable
  Ian J. Garrard, Derek Fisher, and Ian A. Sutherland
  The authors discuss a preparative process using the principles of countercurrent chromatography. This process is faster, capable of loadings from milligrams to hundreds of grams (depending on hardware), and uses robust equipment that can be scaled up easily.
  
• LC TROUBLESHOOTING
  How Do I . . . ?
  John W. Dolan
  For this month's discussion, John Dolan shares some of the key resources that he recommends using when you have one of those "How do I?" questions.
  
• GC CONNECTIONS
  New Gas Chromatography Products at Pittcon 2008
  John V. Hinshaw
  This annual "GC Connections" installment reviews GC instrumentation and accessories shown at this year's Pittcon and also includes some products from Analytica in Munich.
  
• VALIDATION VIEWPOINT
  2008 Method Validation Survey
  Michael Swartz and Ira Krull
  To obtain a better understanding of the challenges faced during method development and validation, the authors - in cooperation with LCGC - conducted a survey earlier this year. This column summarizes the results.
  

ARTICLE

• Performance Qualification of HPLC Instrumentation in Regulated Laboratories
  Jonathan Crowther, Jeremy Dowling, Richard Hartwick, and Bill Ciccone
  With the forthcoming USP monograph <1058>, many laboratories are in the process of re-examining their HPLC instrumentation qualification practices. This article demystifies the qualification procedures and proposes a well designed, easy and simple set of experiments upon which to establish internal SOPs for the complete qualification of HPLC instruments.
  

DEPARTMENTS

• From the Editor
• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  New Chromatography Columns and Accessories at Pittcon 2008: Part II
  Ronald E. Majors
  This month's installment of "Column Watch" is the second part of a two-part series in which columnist Ron Majors examines the trends and highlights in columns and consumables at Pittcon 2008.
  
• LC TROUBLESHOOTING
  Only Three Things
  John W. Dolan
  After taking a course on learning that stated most people only remember three main points from an eight-hour training class, John Dolan decided to use three points in this installment of "LC Troubleshooting," to form the core of a preventive maintenance program for your LC system.
  
• GC CONNECTIONS
  Do's and Dont's
  John V. Hinshaw
  Chromatographers, just like anyone else, develop habits in their daily work. Some of these help create a successful laboratory environment, while others can be ineffective or worse, can create more problems than they solve. This month, "GC Connections" presents a few of the best and worse laboratory habits.
  
• MILESTONES IN CHROMATOGRAPHY
  Farewell to "Milestones in Chromatography"
  Leslie S. Ettre
  After nearly 10 years of writing "Milestones in Chromatography," resident historian Leslie Ettre will step down from his position as an LCGC columnist.
  

ARTICLE

• Detection of Doping Agents by LC-MS and LC-MS-MS
  K. Deventer, O.J. Pozo, P. Van Eenoo, and F.T. Delbeke
  In the last decade, research on the detection of all groups of doping agents has been investigated by LC-MS, and routine LC-MS screening applications are now available for almost all classes of doping agents. In addition, improvements in MS technology with respect to scan speed, sensitivity, and polarity switching now allow for the combined detection of different classes of doping agents.
  

DEPARTMENTS

• From the Editor
• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  New Chromatography Columns and Accessories at Pittcon 2008: Part I
  Ronald E. Majors
  This month's installment of "Column Watch" is the first of a two-part series in which columnist Ron Majors examines the trends and highlights in columns and consumables at Pittcon 2008. Here, he discusses new high performance liquid chromatography (HPLC) columns and packings, including reversed-phase, ion-exchange, ion chromatography, sizeexclusion, and specialty columns.
  
• LC TROUBLESHOOTING
  Ion Pairing - Blessing or Curse?
  John W. Dolan
  After teaching a training class in China, John Dolan was reminded of how chromatographers worldwide encounter the same types of problems. One of these was method transfer, and this month's column is dedicated to method transfer problems.
  
• MS - THE PRACTICAL ART
  Petroleomics - MS from the Ocean Floor
  Michael P. Balogh
  Recent work suggests that the practical value of hyphenated techniques is limited by difficulties inherent in achieving definitive compositional answers in general mass spectrometry (MS) practice. But given knowledgeable hands and the most advanced instrumentation, it is not impossible to do so in certain cases.
  
• DIRECTIONS IN DISCOVERY
  Recent Developments in High-Abundance Protein Removal Techniques
  Tim Wehr
  In the last year, two new protein depletion products have been introduced, and these will be the focus of this month's installment of "Directions in Discovery."
  

ARTICLE

• APPI: The Second Source for LC-MS
  J. A. Syage, L. C. Short, and S.-S. Cai
  This article explores the progress that atmospheric pressure photoionization (APPI) has made in its relatively short history for LC-MS analysis. Specifically, the authors examine the combination of APPI and electrospray ionization (ESI).
  

DEPARTMENTS

• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Glossary of HPLC/LC Separation Terms
  Ronald E. Majors
  In 2001, the second glossary of common and not-so-common terms and "buzz words" for reference to HPLC columns and column technology was published. It is time for an update since new terms have arisen or, in some cases, their original meanings have expanded or changed.
  
• LC TROUBLESHOOTING
  Ion Pairing - Blessing or Curse?
  John W. Dolan
  Reversed-phase liquid chromatography (LC) is a simple and easy-to-use technique that will give satisfactory separations for the samples that most of us encounter. Here, John Dolan examines the pros and cons of this technique.
  
• MS - THE PRACTICAL ART
  Hardware and Software Challenges for the Near Future: Structure Elucidation Concepts via Hyphenated Chromatographic Techniques
  Tobias Kind and Oliver Fiehn
  This month, guest columnists Kind and Fiehn discuss smallmolecule structure elucidation (excluding peptides) using hyphenated chromatographic techniques, mass spectrometers, and other spectroscopic detectors.
  
• VALIDATION VIEWPOINT
  Developing and Validating Dissolution Procedures
  Michael Swartz and Ira Krull
  This month's "Validation Viewpoint" installment highlights some method validation guidelines used in developing and validating dissolution test procedures.
  

ARTICLES

• Characterization and Prediction of Emulsification Performance of Acacia Gums
  Saphwan Al-Assaf and Glyn O. Phillips
  The authors use GPC coupled online to multiangle laser light scattering, refractive index, and ultra violet (UV) detectors for the characterization of Acacia gum (gum arabic).
  
• Quantifying an Anthrax LF Inhibitor in Human Plasma by HPLC-MS-MS
  Melanie Anderson, Richard Simpson, Laura Archer, and Rajesh Desai
  This article describes the method development and performance characteristics of the validated LFI assay and evaluates stability in human plasma.
  

DEPARTMENTS

• From the Editor
• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index

COLUMNS

• COLUMN WATCH
  Approaches to High-Speed Separations in HPLC
  Ronald E. Majors
  In this installment of "Column Watch," Ron Majors examines the various approaches to increasing the speed of high performance liquid chromatography (HPLC) separations.
  
• LC TROUBLESHOOTING
  Flow Rate Adjustment and System Suitability
  John W. Dolan
  This month's "LC Troubleshooting" installment examines the possible reasons your retention times could have changed. If the root cause can be identified and corrected, no adjustment in flow rate will be necessary.
  
• GC CONNECTIONS
  Using Computerized Pneumatics - Part II
  John V. Hinshaw
  The second part of the series takes a look at what happens to the pneumatic operating conditions and chromatography with GC oven temperature programming of a wide-bore column.
  
• MILESTONES IN CHROMATOGRAPHY
  The Beginnings of Gas Adsorption Chromatography 60 Years Ago
  Leslie S. Ettre
  Work done 60 years ago at the University of Innsbruck (Austria), representing the start of gas chromatography, is outlined in this month's column.
  

ARTICLES

• Analysis of Pharmaceutical Residual Solvents Using Comprehensive Two-Dimensional Gas Chromatography
  Christina M. Crimi and Nicholas H. Snow
  Comprehensive GC3GC was employed for the separation of ICH and USP 1, 2, and 3 pharmaceutical solvents. The significantly improved peak capacity in GC3GC allows a single method for any combination of solvents and mitigates interference due to impurities in the solvents, diluents, analyte matrices, and from column or septum bleed, through the increased separation space.
  
• Column Selection for Two-dimensional LC3LC
  Pavel Jandera
  This article describes the factors that affect the selection of columns for two-dimensional (2D) LC3LC separations.
  

DEPARTMENTS

• From the Publisher
• Peaks of Interest
• Products
• Literature
• Classified Directory
• Ad Index