Archive for 2012

Contamination and Troubleshooting: “Jack, did that really happen?”

I had to blog on this because this just happened again to my colleague Jack last week! Occasionally, a loose spring will make it into a limited volume insert. If overlooked, sample is loaded into this insert. As the spring soaks in the sample, a significant background signal can result. The green chromatogram trace shows […]

Troubleshooting your Micro-Ion Vacuum Gauge

Last month, I promised an explanation on why the vacuum gauge no longer works on my 5975C. This past year, we have been experimenting a lot with Concurrent Solvent Recondensation – Large Volume Splitless Injection (CSR-LVSI). Unlike most large volume injection techniques, CSR-LVSI does not vent excess solvent before transferring analytes to the analytical column. […]

Selectivity differences for drugs of abuse when using Rxi-5ms and Rxi-5Sil MS GC columns: pendant diphenyl versus silarylene stationary phases.

Previously I had written about seeing differences in selectivity when analyzing pesticides on Rxi-5ms and Rxi-5Sil MS GC columns.  As you may remember (if you’re younger than me because I can’t remember almost anything these days!), the 5ms is a 5% pendant phenyl column and the 5Sil MS has phenyl content in the siloxane stationary […]

Handling Your Analytical Reference Standards

Readers of the blog have been presented with a wealth of information on for their GC columns, LC columns, detectors, syringes, carrier gases, TO-Canisters, and the list go on. What’s missing? Analytical Reference Standards. Although not all reference standards have special handling instructions, the following general guidelines should assist you with the proper handling of […]

It’s a confusing time for GC/MS analysts

I don’t know about you, but the more information I hear about switching from helium to hydrogen as a carrier gas, the more confused I get. When the helium shortage started, there were articles stating that this was a minor hiccup in the processing/supply chain, and capacity & inventories would be restored by the fall. […]

EZGC Made Even Easier – Free web version now available!

A few of my colleagues, Julie Kowalski and Chris English, have written blogs about the original CD based Pro ezGC modeling software (ezGC really IS cool! and Pro ezGC Software: Manna from Heaven or a Clunky DOS-Based Program).  The basics of this software is to add a library of compounds by entering the retention times […]

Live Long and Prosper-How to make your HPLC columns last longer

We frequently get questions about how long an HPLC or UHPLC column should last. To borrow a phrase from my colleagues, “Your mileage may vary.”  Columns are like cars, so their lifetime depends how they are used and how well they are maintained. That being said, some phases are known to be more rugged than […]

Light hydrocarbon analysis in water samples – not just a headspace method anymore

Living in Pennsylvania during this natural gas boom stirs passionate, mixed emotions about the economic benefits verses the environmental costs of drilling for this resource. While it is tempting to provide you all my thoughts on the subject, I’ll keep my opinions to myself and simply provide our blog readers some interesting information I recently […]

Which LC Phase Do I Need?

So you’re thinking about doing HPLC (or UHPLC) and don’t have a method? You’ve never even seen a method for anything remotely similar. You might have even searched our HPLC chromatogram database for the application and haven’t found anything.  (After all, that’s the quickest and easiest way to get some ideas.) What to do… Let’s […]

Method TO-15 Requirements – Part I: “There’s more than one way to skin a cat”

Over the past several months, I have had several inquiries on the requirements of the U.S. EPA’s Compendium Method TO-15 (Determination of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS)). So I thought it might be useful for potential end users of said method to be […]