Archive for the ‘Miscellaneous’ Category

Chiral separation on a C18 column? Separation of d- and l-amphetamines, Part II

To continue my blog part 1 (Part 1:https://blog.restek.com/?p=67087) , where I have briefly discussed the importance of separating the d and l isomers to accurately identify the illicit isomer using an achiral method on a Raptor C18 column employing a pre-column derivatization technique. Today I’d like to discuss more about the matrix of interest, sample […]

Amines: Topaz or Base Deactivated Liners?

Amines can be difficult to analyze by GC, since they are active and adsorb to surfaces within the chromatographic system, including the inlet liner and the column.  This leads to loss of compound response, and peak tailing.  While deactivations can help to mitigate these effects, the quality of deactivations varies.  Primary amines are especially difficult, […]

Tetrachlorobenzene isomers added to ProEZGC!

Tetrachlorobenzenes are manufactured as intermediates for the production of fungicides, herbicides, defoliants, insecticides as well as dielectric fluids for transformers (1). There are three isomers with the following chlorine substitutions; 1,2,3,4 / 1,2,3,5 / 1,2,4,5. While the chemical industry measures these compounds for purity they are also found in the environment as the result of […]

What’s in your mouse feed?

When it comes to different types of GC techniques, headspace (HS) analysis is about as clean as they come. Typically, hundreds of injections can be made without doing any inlet maintenance or column trimming. It is one of my favorite techniques in the lab since it encompasses countless different unique applications. Even though HS is […]

GC Inlet Liner Selection, Part IIB: Split Liners Continued

My colleague, Alan Sensue, asked a couple of great questions in regards to my previous blog post on split liners.  To summarize, he was interested in what happens to responses for the various liners when you change split ratios.  For instance, if you go from a 20:1 split to a 40:1 split, do detected peak […]

Thrive with the New Rxi-65…TG!

Introducing our new and improved GC stationary phase: The Rxi-65TG! This column is essential for analyzing triglycerides in edible oils! You may be asking yourself, why the need for a new 65-type phase? Well, we certainly were not happy with the way our current Rtx-65TG was performing. After redeveloping the polymer and using Rxi technology, […]

GC Inlet Liner Selection, Part II: Split Liners

In the previous installment of this blog series, I discussed liner selection for splitless analyses (GC Inlet Liner Selection, Part I: Splitless Liner Selection).  Today I’d like to discuss liners for split analyses.  During a split injection, the split vent is open and the majority of the flow is vented.  The split ratio, set by […]

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 […]