Author Archive

Difficult QuEChERS extracts: Removing fatty acid interferences

Using the QuEChERS extraction and cleanup method for high fat commodities such as, nuts, dairy, fish, and avocado can be difficult to analyze for pesticide residues.  Using the dispersive solid phase (dSPE) cleanup sometimes is just not enough to adequately remove the fatty acid co-extractives. Check out this technical article on how to quickly yet […]

Wildfires in the Western United States: The smoke can be as dangerous as the flames, especially for firefighters.

The drought continues and wildfires are raging across the Western United States.  In Washington State alone, the wildfires have burned over 1400 square miles (that’s 3600 km2).  Brave men and women from across the United States are coming to the aid and trying to contain these historical fires.  Unfortunately lives of the firefighters are in […]

Another cup of PAH tea please!

It seemed not too long ago that Julie Kowalski and I were analyzing tea, a lot of tea, and only tea.  To this day we cringe at the thought of tea, but hopefully our pain can be your gain. We analyzed pesticides, natural products, and polycyclic aromatic hydrocarbons (PAHs) in tea.   Julie and Amanda Rigdon […]

Which GC instrument should I use for the analysis of pesticides in herbal tea? GC-MS/MS or GCxGC-TOFMS?

You may remember a while ago I posted a blog about the analysis of herbal tea using QuEChERS and GCxGC-TOFMS.   The LECO Pegasus GCxGC-TOFMS is a great instrument for analyzing complex samples because of the comprehensive chromatographic separation achieved (two columns with different selectivities).  The GCxGC-TOFMS also excels at non-target screening of compounds.  Lucky for […]

Inject more fish extracts before GC maintenance is needed using shoot-and-dilute GC

Persistent organic pollutants (POPs) like dioxins, furans, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ether (PBDEs) are lipophilic and therefore may be found in fatty matrices like fish.  In order to remove the high lipid coextractives, lengthy cleanup procedures that require multiple cleanup cartridges are often used.  I recently presented work at the Dioxin meeting where […]

Fast Sample Preparation and Shoot-and-Dilute GC for Flame Retardants in Fish

The shoot-and-dilute GC technique (split injection) is perfectly matched for the fast sample preparation approach of QuEChERS.  The QuEChERS concept provides a fast, multi-residue extraction and “just enough” cleanup.  The technique is quick and minimizes solvent usage, but the resulting extract can contain a large amount of coextracted nonvolatile material.  A split injection is an […]

The North American Chemical Residue Workshop – Sharing Science and Fun in the Sun

NACRW kicked off again with the Restek Vendor Seminar.  We shared dinner and drinks while Jonathan Keim gave a very informative presentation highlighting some of the uses of the Restek EZGC Method Translator and Flow Calculator.  The translator/flow calculator has many uses including: Translating methods to increase speed of analysis by decreasing column length, decreasing […]

Flame Retardants on my Mind and on Your Electronics and Your Furniture and….

I recently returned from the Brominated Flame Retardant Workshop in Indianapolis, Indiana. Going to a conference that covers analytical, occurrence and fate, biological and toxicology really puts what Restek does and the products that we make into perspective. Being able to analyze flame retardants in biotic and abiotic matrices is only the first challenge. The […]

Spring is finally here! Unfortunately so are the ticks…

After a long and cold winter here at the Restek headquarters in Bellefonte, PA, USA it seems that spring is finally here!  It is so nice this time of year to get outside and enjoy the weather and the beautiful outdoors that Pennsylvania has to offer.   Unfortunately after a hike in the woods there is […]

Are fatty acids overwhelming your QuEChERS dSPE PSA cleanup and causing issues in your GC analysis? Get more cleanup capacity with cartridge SPE cleanup!

Fatty acids are important molecules in the human body because they are used as a source of fuel.  There are many food sources of both “healthy” and “unhealthy” fatty acids.  Many sources of dietary fatty acids come from fruits, vegetables, seeds, nuts, and animal fats.  The QuEChERS methodology was developed to analyze pesticides in fruits […]