Archive for the ‘GC/MS’ Category

Quadrupole Scan Speed and the 8270 Instrument Checkout Mix

In my last blog (here), I promised an update on the impact of the detector scan speed on the tailing factor. I had speculated that a pentachlorophenol tailing factor value of 0.94 was more likely < 1.0 because of the scan rate, rather than column overload. The examples I put forward here were collected on […]

Cannabis Residual Solvents Using MS Detection – I’m Not Hungry but I’ll Eat My Words Anyway

After coming back from a huge lunch at the Bellefonte Wok, a favorite Restek lunch spot, I’m completely stuffed, but I have to eat my words from a previous blog. In this blog, I made the case against using MS detection for headspace analysis of residual solvents in cannabis concentrates due to interference between the […]

An introduction to the benefits of using split injection when performing semivolatiles analysis by 8270D – the instrument checkout mix

This blog is part of a series; the previous installments can be found here and here. We have mentioned several times that the reduced residence time resulting from the fast sample transfer that occurs during a split injection reduces in-inlet degradation and adsorptive loss. Proof of this can be seen in the first run of […]

Looking for a Cryogenic Valve for your Shimadzu GC-MS?

I was working on a project for volatile sulfur analysis. It took so long to cool the GC oven to 30 °C, and yet the most volatile analytes were still difficult to separate. At that time, I realized that I needed a cryogenic cooling system for my Shimadzu GC-MS QP2010 plus! However, I was not as excited as […]

Simple Analysis of Bile Acids by GC-MS

Bile acids are a group of steroidal acids with carboxyl and hydroxyl groups on the side. They are the major metabolic products of cholesterol. Bile acids play important roles as biomarkers for early diagnosis and therapeutic monitoring of many diseases, especially liver and intestinal diseases. For instance, high levels of intestinal bile acids, in particular, […]

GC-API-MS for BDEs with N2 at BFR2016

OK Jack, enough of the acronyms; this isn’t a word puzzle… Recently I let ChromaBLOGraphy readers know of our work on using gas chromatography (GC) with atmospheric pressure ionization (API) – mass spectrometry (MS) for analysis of brominated diphenyl ethers (BDEs) employing nitrogen (N2) carrier gas, which was presented at BFR2016 (BFR standing for Brominated […]

Restek at BFR2016 in Toronto – APGC of Brominated Flame Retardants Using Helium and Nitrogen Carrier Gases

In only a few short weeks, I will be giving a presentation on the analysis of brominated flame retardants at BFR2016 in Toronto.  My colleagues and I used an atmospheric pressure ionization mass spectrometer with gas chromatography on an Rtx-1614  (15m x 0.25mm x 0.10µm) column to look at polybrominated diphenyl ethers (PBDEs) in various […]

Split Injection Makes for Easier Polar Solvent GC Work versus Splitless Injection

As anyone who’s doing QuEChERS knows, analyzing acetonitrile extracts on nonpolar GC columns (like Rxi-5ms, e.g.) using splitless injection can be problematic because of the classic solvent – stationary phase mismatch.  To avoid split peaks we usually have an initial GC oven temperature slightly above the 82°C boiling point of acetonitrile (MeCN), but this causes tailing […]

Fast Analysis of PAHs using Split Injection and a Short GC Column

Click on the this link:  Fast Analysis of PAHs  to see how I analyzed the EPA 16 polycyclic aromatic hydrocarbons (PAHs) in under 10 min using GC-MS by employing split injection with a Restek Premium Precision split liner with wool and a 15m x 0.25mm x 0.25µm Rxi-5Sil MS GC column.  Split injection allows a higher GC oven […]

Shoot-and-Dilute GC – Practical GC – The Column

Check out my recently published articles in LCGC – The Column on Shoot-and-Dilute GC (split injection GC), where I outline the benefits of this technique through recently collected experimental data in my lab at Restek.  I’m two articles into my Practical GC series, with another one soon to be published.  This is a continuation of other split injection work […]