Archive for the ‘Miscellaneous’ Category

TO-15 + PAMS + TO-11A = China’s HJ759 + PAMS + HJ683 Part 3: Formaldehyde Sampling in Air Canisters

In my previous blog (TO-15 + PAMS + TO-11A = China’s HJ759 + PAMS + HJ683 part 2: Deans switching and TO-15/PAMS) I covered the combination of the TO-15 and PAMS (or HJ759 and PAMS) methods into a single run using a Deans Switch and FID/MS detector set up. I said that I’d revisit integrating […]

GC Inlet Liner Selection, Part I: Splitless Liner Selection

Splitless injections are used when detection of trace amounts of analytes is necessary and the goal is to recover close to 100% of all analytes that are injected into the instrument.  During a splitless injection, the split vent is closed for a predetermined amount of time, directing all inlet flow onto the column (with the […]

GC Inlet Liner Selection: An Introduction

GC inlet liners play an important role in GC sample introduction. The sample’s first contact is with the liner and from there it is transferred to the analytical column. In the case of liquid injections, the sample must be vaporized inside of the liner prior to transfer.  Choosing a proper inlet liner for your analysis […]

ASTM D 3606 17

Keep your benzene in check with ASTM D3606   While benzene historically has been used as an additive in gasoline and aviation fuel, it is a known toxic air pollutant and is regulated by both the EPA and European Union. While the ASTM has published both capillary and packed column methods this blog will focus […]

Take Care of Your LC System Investment and Minimize Downtime with Routine Maintenance!

For cannabis QA laboratories and producers, developing methods for HPLC analysis of cannabinoids can be time consuming and resource heavy.  While a lot of focus has been given to sample preparation and optimization of method conditions to maximize sample throughput, one VERY critical factor is often  overlooked: routine LC system maintenance. Keeping a log book […]

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 […]

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 […]

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 […]

Are you experiencing helium supply issues and rising costs?

Helium supply issues are nothing new.  At Restek we have been discussing this off and on for years now.  The following articles and information are just a small selection of what is available on our website and our ChromaBLOGraphy, and are there to help you make informed decisions about alternatives to helium, and reduced helium […]