Archive for the ‘Tips & Tricks’ Category

How Can You Make Food Homogenization Less of a Grind?

Sample preparation of a food matrix is only as good as the initial homogenization of your sample.  This determines how representative and effective your extraction will be.  There are multiple ways to homogenize, grind or comminute your sample.  Some involve a simple grind in a food processor.  Other methods require expensive instrumentation to cryogenically freeze […]

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 […]

My fitting nut has broken off in the end of my LC column. What to do?

If excessive force is applied at an angle to a fitting or column connector, the ferrule could become stuck in the column end fitting. Likewise, a PEEK connector, column nut or plug can also break and leave part of it in the end fitting. Stainless steel nuts are much harder to break, although a stainless […]

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 […]

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 […]

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 […]

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 […]