Archive for 2019

A Tale of Two Columns (CLPesticides and CLPesticides2)—Part II: Gaining Speed

In my previous blog post, I gave you a little history of the CLPesticides columns.  You’ll remember that I pointed out the 24 minute run times, which were promoted as being fast at the time.  Fortunately, there are ways to attain faster runs on this column pair for standard 8081 pesticides, due to their awesome […]

A Tale of Two Columns (CLPesticides & CLPesticides2)—Part I: A Little History

Chlorinated pesticides are persistent environmental contaminants commonly analyzed using a variety of GC methods, including US EPA 8081, 608 and 508.  Due to similarities in chemical properties of these pesticides, selectivity must be carefully considered when choosing GC columns.  Historically, columns with phenyl methyl (5% phenyl, 35% phenyl, 50% phenyl columns) and cyanopropyl (1701 column) […]

Pesticides are like Siblings – some get along well and some don’t – No. . .Really?

My colleague, Joe Konschnik and I have been asked by many food chemists out there about how much they can trust their pesticides mixes after they combine them into one single larger mixture for calibrating their instrument, or monitoring the accuracy and precision of their method – and rightfully so.  Well, like siblings, sometimes they […]

Aura Personal Air Samplers for NIOSH Canister Method 3900

The National Institute of Occupational Safety and Health (NIOSH) has published their “Volatile Organic Compounds, C1 to C10, Canister Method 3900” in the NIOSH Manual of Analytical Methods (NMAM), Fifth Edition. In short, the method is a variant of United States (U.S.) Environmental Protection Agency (EPA) Method TO-15; however, with a focus on a particular […]

TO-15 + PAMS + TO-11A = China’s HJ759 + PAMS + HJ683

It is very fitting that I write this blog while I am in Shanghai, China. The impetus for this blog, and the blogs to follow, is that the Chinese Ministry of Ecology and Environment (formerly the Ministry of Environmental Protection) published their “VOCs Monitoring Scheme of Environmental Air Quality.” In short, this standard outlines the sampling […]

Choosing Your Citral Column

The name ‘citral’ or 3,7-dimethyl-2,6-octadienal, suggests the scent of lemons so it’s not surprising that another name for this compound is lemonal. There are two isomers of this compound with the same chemical formula (C10H16O); geranial (citral A) and neral (citral B). As seen in the image to the right, the difference between these compounds […]

Paul’s excellent questions on “Liner Selection for HS VOCs”

I had a feeling the blog I posted yesterday was sure to prompt some thought-provoking questions, as some of my peers had already been doing so. So, it came as no surprise that Paul posted the following excellent questions (in black) to which I have responded to in blue. Normally, I would just address all […]

SPME Fundamentals: Liner Selection for HS VOCs

My colleague Linx Waclaski is usually the one doling out excellent liner advice, so bear with me as I take a crack at this liner stuff. Ever since we came out with traditional SPME and the SPME Arrow, a lot of customers have had concerns/questions regarding SPME liner dimensions. The short answer to most of […]

What dSPE works with spinach in GC-MS/MS analysis? #NationalSpinachDay

Today is a National Spinach Day! What is a better way to celebrate than to talk about spinach analysis? During part 1 of my blog series, I discussed what dSPE was best for celery. I found that most dSPE, with the exception of dSPE containing high amounts of graphitized carbon black (GBC), showed acceptable analyte recovery […]

3-MCPD blog part 2: How hot we can go with inlet and can we use regular split/splitless inlet?

In my last blog, I (hopefully!) made a case that switching to split injection for analysis of 3-MCPD esters is a viable option. Now I’d like to show that if we stick to split, we can also use much higher temperatures and if we can do that, we can also use regular split/splitless inlet. To […]