Archive for the ‘Enviro’ Category

Hydrocarbon Ranges of Natural Gas and Petroleum Products

Sometimes customers need to analyze natural gas and petroleum products, whether it is to confirm the purity of the product by looking for the impurities which may be present, or for an environmental reason such as a spill or leak.  In order to choose the correct GC column and reference standards, one needs to know […]

Modifying QuEChERS for complicated matrices- High Fat Samples

This post is part of a series on QuEChERS. Here are links to the previous two posts, in case you may wish to catch up before reading this one: QuEChERS dSPE selection-which one is best? Modifying QuECHERS for complicated matrices- Dry Samples (See Jana’s post here for further details on dry samples: QuECHERS approach optimization […]

Cryogenic Cooling for Air Analysis Part 2 – Combining TO-15A and Ethylene Oxide

In my previous blog on cryogenic cooling (https://blog.restek.com/cyrogenic-cooling-for-air-analysis-interferences-from-n2-co2-and-o2/) I touched briefly on ethylene oxide (EtO) and why it may be of interest in ambient air analysis. While OSHA has a time weighted average (TWA) limit for EtO at 1ppm for an 8 hour exposure, recent work by the US EPA has shown that even low […]

Quechers dSPE selection- which one is best?

Method development for Quechers sample cleanup can be a complicated task. Not only does the analyst need to make sure their analytes of interest can be recovered, but the matrix interferences must be removed enough to make the quantitation possible and reliable. It makes sense that selecting the best dSPE products is highly dependent on […]

Are PFAS sticking in your system?

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in our society and can be found in a wide range of consumer products; hence they are widely present in the environment, people and animals. They are persistent chemicals that have the potential to accumulate. Therefore, they are evaluated and monitored using a variety of methods and controlled […]

Pro EZGC Update: Comprehensive 209 compound Library of Brominated Diphenyl Ethers and a New Column Format

While attending Dioxin 2018 in Krakow, I noticed that several academic researchers were studying  the toxicity of specific PBDE congeners not on the standard target compound list for EPA method 1614 (or the EU equivalent). Though PBDE mixtures have been phased out of production and use, the concentrations in the environment have not been declining […]

Falling Victim to One of LC’s Classic Blunders: Mismatching Your Diluent and Mobile Phase

An early lesson most of us learn in liquid chromatography is this: Always match your diluent to your mobile phase.  Once the exams are done, if you learned this in a college course, or your manager has walked away, you start flexing this “requirement” a little to see how matched they really need to be.  […]

Two for the Price of One? Using CPP to Simultaneously Clean Pesticide and PCB Extracts

In a recently published blog, we introduced the advantages of cleaning EPA Method 8081 extracts using CarboPrep Plus (CPP) as a replacement.  The sample preparation for PCBs by EPA Method 8082 is commonly combined with the pesticides EPA Method 8081 for the extraction step then split into two portions for sample cleanup.  The logical question […]

Glycols…. Tis The Season!

Tis the season to be thinking about glycols…. Why you ask?  Well its currently winter as I’m writing this and glycols, specifically propylene glycol (PG) and ethylene glycol (EG), along with other ingredients, are used in airports for deicing planes.  Propylene glycol based fluids are more common since they are less toxic than ethylene glycol […]

Got Fast Columns? Clean Up Your 8081 Samples Using CarboPrep Plus as a Substitute for Florisil

My colleague Linx Waclaski blogged about a tale of two columns that started with the introduction of a pair of stationary phases specifically tuned for the resolution of the 20 legacy pesticides found in US EPA Method 8081(1). The story examined the gains in speed over the years as measured by the last eluting compound […]