論説

Articles

Achieving Faster GC

Numerous articles have been published on faster methods for gas chromatography (GC), yet uncertainty remains on how best to speed up separations. Here, Dr. Hans-Gerd Janssen clarifies the confusion surrounding fast GC and recommends a strategic approach based on 3 steps: 1) minimizing resolution to a value just sufficient, 2) maximizing the selectivity of the chromatographic system, and 3) implementing a method that reduces analysis time while holding resolution constant.

Analysis of Brominated Flame Retardants by Liquid Chromatography Mass Spectrometry

Dr. Chris Marvin, of Environment Canada, discusses the challenges of analyzing brominated flame retardants, such as polybrominated diphenyl ethers, by LC/MS.

Are GC Techniques Really Optimized?

Those new to chromatography often assume that basic techniques have been optimized, but, as with splitless injection, this is not necessarily the case.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Assuring Accuracy of GC Results

Even validated methods run on certified equipment are unlikely to be foolproof. Real quality assurance needs to be based on direct verification using internal standards and control samples.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Carrier Gases for GC

Want to know why hydrogen is the best carrier gas for GC? Dr. Konrad Grob discusses how carrier gas choice influences chromatography, focusing on diffusivity and viscosity.

Certification of injectors and injection techniques?

While splitless injection is a common technique, injectors and operator experience vary considerably and can be significant sources of error.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Comprehensive 2D Gas Chromatography — Making GC Separations Work Harder

Guest editor Dr. Phil Marriott tells us the three primary contributions ascribed to GCxGC are greater separation capacity, greater sensitivity, and a data presentation that permits identification of related compounds based on the molecular properties that control retention. The most significant advantage is separation power: to be able to resolve many more compounds immediately enables a much more complete ‘picture’ of the composition of a sample.

Do We Need a Chromatography School?

As quality management systems constrain creativity in chromatography and educational standards dwindle, Dr. Konrad Grob contemplates the factors that got us here and how we can train new leaders in our field.

Food Technology -- Are We as Safe as We Think?

A thought-provoking discussion of the risks of rapid technology advancement and food safety.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Matrix Effects in Multi-Residue Pesticide Analysis When Using Liquid Chromatography-Tandem Mass Spectrometry

Matrix effects present a significant challenge to multi-residue pesticide analysis of food samples using LC/MS/MS. In this editorial, Dr. Kai Zhang, of the FDA Center for Food Safety and Applied Nutrition, discusses approaches that minimize matrix effects.

POPs: Stay Off! Stay Away! Stay Alive!

Jean-François Focant, Associate Professor at the Chemistry Department of the University of Liège in Belgium, writes about human exposure vectors for persistent organic pollutants.

Preventive Maintenance for GC

Professor Jennings explains the consequences of ignoring those enclosures included with a new column, and offers simple, proven, preventive maintenance options that help avoid downtime.

Quality Control in Metabolomics

Metabolites are found in different concentrations in complex biological matrices and are very difficult to extract without compromising their structural integrity and relative abundances. Quality control in metabolomics means more than just taking care of chromatographic or mass spectrometry parameters. This article by Oliver Fiehn examines quality control as an attitude towards gaining reliable data, rather than an automatic procedure implemented in instrument software.

Restek: A Company of Owners

In this editorial, founder and former CEO Paul Silvis explains some of the reasons for Restek's success as a provider of chromatography columns and supplies. Restek will continue to be successful because, as an employee-owned company, we hold our future in our own hands. Customers will benefit because we can continue to respond to their ideas for the products and services they need to make their work easier.

Retention Cross-over Phenomenon in Gas Chromatography — Can the Mystery be Revealed?

Dr. Werner Engewald discusses the phenomenon of cross-over, or changes in elution order following modification of the GC temperature program. This effect has been observed for decades but the physio-chemical background still is not well understood. In this article Dr. Engewald explores the theory and potential explanations for the cross-over phenomenon.

Sample Evaporation in Hot GC Injectors

Proper sample evaporation in the injection port cannot be assumed. Principles governing evaporation are discussed.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Sample Evaporation in Splitless Injection

The rule of using empty liners with splitless injection was developed in the days of manual injections. Does it still hold true? Sample evaporation is explored.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Sample Preparation Techniques Used for Gas Chromatography

Sample preparation principles and techniques for gas chromatography are reviewed. Techniques include: static headspace, dynamic headspace, solid phase extraction and microextraction, distillation, stir bar sorptive extraction, Soxhlet, accelerated solvent extraction, pressurized liquid extraction, subcritical water extraction, microwave assisted extraction, ultrasonic extraction, and supercritical fluid extraction.
By Robert L. Grob, Ph.D., Emeritus Professor of Analytical Chemistry, Villanova University

Selectivity in Gas Chromatography

In this guest editorial, Dr. Colin Poole of Wayne State University discusses the role of selectivity in gas chromatography. Dr. Poole has published numerous papers and books on the separation and detection of small molecules in biological, environmental, and food samples.

Sitting Down with a Chromatography Icon:
Dr. Robert Sternberg

Dr. Robert Sternberg received his PhD in electrochemical biosensors and worked on the development of a glucose sensor in an artificial pancreas for 10 years before joining an emerging field of astrobiology. This started a 37-year career in analytical chemistry that would play a critical role in the success of the Cassini-Huygens, Curiosity, ExoMars, and most recently the Rosetta mission. His areas of interests are in the characterization for organic molecules in extraterrestrial environments. He is currently a senior lecturer of chemistry at University of Paris and is head of the GC space instrumentation group at Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA). Dr. Sternberg and the European Space Agency (ESA) have been working with Restek, using our columns and Pro ezGC software on their missions, for over 15 years. With the Rosetta spacecraft and its Philae lander making the news recently, we caught up with Dr. Sternberg to discuss his work.

Sitting Down With a Chromatography Icon: Pat Sandra

Restek’s Jaap de Zeeuw sat down for an interview with chromatography icon Pat Sandra. They discussed Professor Sandra's education and background, his firsthand involvement with advancing the field of chromatography, the founding of Riva, future plans for his new company PaSaTiempo, and much more.

Sitting Down With a Chromatography Icon: W. George Fong

Restek’s Jack Cochran sat down for an interview with chromatography icon W. George Fong. They discussed George’s founding of FPRW in the 1960s, FPRW's growth from a small intra-lab meeting into an international event, George's involvement in the history and future of pesticide residue analysis, and more.

The "Replacement" Column

In his first contribution to the Restek Advantage Professor Walter Jennings discusses why analysts often encounter problems when replacing a capillary GC column, and provides a solution.

The GC Separation Process

Dr. Konrad Grob presents a visual concept of the forces behind chromatographic separation. The relationships among phase, flow, temperature, and capacity are explored.

The Role of Selectivity in Liquid Chromatography Method Development

Dr. Schug, Associate Professor and Shimadzu Distinguished Professor of Analytical Chemistry in the Department of Chemistry and Biochemistry at The University of Texas at Arlington, discusses the role of column selectivity in liquid chromatography method development.

The Value of Education

Is analyst certification a good idea? Maybe or maybe not, but an educated analyst can develop and troubleshoot methods efficiently and is a cost-effective asset in the laboratory.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Unraveling Scent Signals to Protect African Wild Dogs

Dr. Peter Apps discusses how gas chromatography is being used to help protect endangered African wild dogs from conflicts with humans in Botswana.

Using Guard Columns and Retention Gaps in GC (Part 1)

Guard columns & retention gaps are used widely in gas chromatography (GC) but the differences between them are not always understood. Part 1 of this two-part editorial by Jaap de Zeeuw reviews the use of retention gaps & discusses critical factors affecting performance. This sets the background for Part 2, which details guard columns & introduces a new segment coating technology that allows retention gaps & guard columns to be built directly in the same piece of tubing as the analytical column.

Using Guard Columns and Retention Gaps in GC (Part 2)

Guard columns & retention gaps are used widely in gas chromatography (GC) but the differences between them are not always understood. Part 2 of this two-part editorial by Jaap de Zeeuw discusses guard columns & introduces a new segment coating technology that allows retention gaps & guard columns to be built directly in the same piece of tubing as the analytical column.

Why 5cm syringe needles for capillary GC?

A detailed discussion of how syringe needle length impacts quantitative analysis. Includes optimal needle lengths for different scenarios.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Why Uncoated Capillary Precolumns Enable Injection of Large Volumes

Discussion of the origins of the retention gap, a length of uncoated tubing used to focus large volume injections and prevent band broadening.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich

Working Safely with Hydrogen as a Carrier Gas

Hydrogen offers a number of benefits over helium as a carrier gas for gas chromatography. With basic safety measures in place, labs can safely use hydrogen for faster chromatography.
by Dr. Konrad Grob, Kantonales Laboratory, Zurich