Author Archive

Why Biphenyl is a very interesting primary choice as stationary phase in LC..

Being a GC chemist for almost 38 years I always wondered why most LC separations are performed on a C18. A C18 is an extremely good non-polar stationary phase and is the foundation of reversed-phase chromatography, where polar mobiles phases are used with non-polar stationary phases. But there are so many C18 phases, how do […]

Analysis of N2O (nitrous oxide) via GC: an update

Nitrous oxide (N2O), is commonly known as “laughing” gas, but is also used as a component in fuels in rockets and as an aerosol propellant. N2O is itself a stable gas and can be analyzed relative easy via gas chromatography. Often it is confused with “nitric oxide”, (NO). NO is a very reactive gas. When […]

Pesticides/Fungicide cocktails responsible for Death of Bees: analysis via GC-MS

  Researchers at the University of Maryland and the US Department of agriculture may have uncovered the mystery of high mortality in honeybees. These insects are responsible for pollinating over 130 different crops in the US alone. Loss of this pollinator species could cost the US $15 Billion annually. The EU (European Union) issued a […]

[28] What do Chromatograms tell us? First Eluting Peaks are very Broad when using Direct Injection and Water as Matrix.

Chromatograms are like fingerprints. If you can “read” chromatograms well, you often can find a plausible cause. In this series, we will show a series of GC-chromatograms that are obtained from users and discuss some potential causes for the phenomena. Then we can move into some solutions for improvement.     Direct injection is often […]

Injection Techniques used in GC: Names and What are we actually doing with each Technique?

  When traveling around I experience a lot of confusion on the naming of Injection techniques in Gas Chromatography.  The challenge can be the “mode” settings of the GC. Often the GC does not use the same name as what the actual technique is what we are using.       Split injection The sample is […]

[26] What do Chromatograms tell us? Base line goes up and shows a “hump” after each analysis..

Chromatograms are like fingerprints.  If you can “read” chromatograms well, you often can find a plausible cause. In this series, we will show a series of GC-chromatograms that are obtained from users and discuss some potential causes for the phenomena. Then we can move into some solutions for improvement.   When using GC sometimes the […]

[25] What do Chromatograms tell us? My peaks broaden and look worse after every analysis: Impact of the Transfer Line in GC-MS

  Chromatograms are like fingerprints.  If you can “read” chromatograms well, you often can find a plausible cause. In this series, we will show a series of GC-chromatograms that are obtained from users and discuss some potential causes for the phenomena. Then we can move into some solutions for improvement.   This was an interesting […]

Poster on sources for “Ghost-Peaks” in Gas Chromatography

During  last International symposium on micro-column separation sciences, in Riva del Garda, Italy, Restek presented a poster on “Sources for Ghost peaks in GC”.   This poster was a summary of 5 publications which all focused on the sources of Ghost peaks. We received several inquiries for a copy of the actual poster, as users […]

Column Cutting, for making the Optimal Coupling: Do you use your Column-Scoring-Wafer the Right Way?

Column cutting is an activity that is done many times in the lab. When maintenance is done, often a piece of the column inlet is also cut off. There are an increasing nr of methods, where columns have to be coupled. When using Guard columns, Pre columns (coated guard columns), Retention gaps, transfer tubing or […]

Do I smell Cannabis in the Lab?

Last week I was traveling in Europe to present seminars on practical topics like trace analysis, faster analysis and troubleshooting. During such seminars you visit companies and you always learn something.  One of the companies we visited was a company that did forensic analysis and were specialized in cannabis measurement.  My colleague already explained to […]