Author Archive

GC Inlet Liner Selection, Part III: Inertness

The inlet liner is the first surface analytes will interact with after introduction into a GC.  It is critical that liners are deactivated, as a number of adverse interactions can occur between analytes and the glass surface.  Deactivations typically involve some type of silanization of the surface to cover active sites inherent in glass, such […]

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, […]

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 […]

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 […]

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 […]

A Tale of Two Columns (CLPesticides and CLPesticides2)—Part IV: Fast 8081 Method Using GC Accelerator Kit

The moment has finally come to see how we can use the GC Accelerator to get the most horsepower for your 8081 analysis.  If you’ve been following this blog series, you will remember that in Part II, I talked about ways to make your runs faster.  I also showed you our previous fast “7 minute” […]

A Tale of Two Columns (CLPesticides and CLPesticides2)—Part III: Using the GC Accelerator Kit for Dual Column Analyses

In my previous two blogs (Part I and Part II), I mentioned the use of Restek’s GC Accelerator Oven Insert Kit (cat. #23849) for making your methods even faster.  The GC Accelerator kit was originally released with the intent of being used with an Agilent GC-MS system; however, this same kit can also be used […]

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) […]