Archive for the ‘Food’ Category

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 […]

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 […]

Fast gas chromatographic residue analysis in animal feed using split injection and atmospheric pressure chemical ionization tandem mass spectrometry

In a recent ChromaBLOGraphy post I mentioned that we are doing a campaign on “shoot-and-dilute GC”, also known as split injection GC, at RAFA 2015. A paper just published by Tienstra, Portolés, Hernández, and Mol used split injection with APGC for pesticide and other residue analysis in animal feed to achieve many of the benefits we’ve been […]

7th International Symposium on Recent Advances in Food Analysis (RAFA)

The 7th International Symposium on Recent Advances in Food Analysis, better known in short as RAFA, starts this week in Prague, The Czech Republic.  This is my tenth anniversary for this biennial meeting, where the organizer, Jana Hajšlová, invited me to give the lecture, Using the QuEChERS Sample Preparation Method and GCxGC-TOFMS to Determine Pesticides […]

Difficult QuEChERS extracts: Removing fatty acid interferences

Using the QuEChERS extraction and cleanup method for high fat commodities such as, nuts, dairy, fish, and avocado can be difficult to analyze for pesticide residues.  Using the dispersive solid phase (dSPE) cleanup sometimes is just not enough to adequately remove the fatty acid co-extractives. Check out this technical article on how to quickly yet […]

Raptor Biphenyl LC Columns provide the data needed for global antibiotic testing

Because the widespread use of preventative veterinary antibiotics has resulted in increased antimicrobial resistance in humans, the US Food and Drug Administration (FDA) released guidelines to address the issue in food animals (December 11, 2013). Similar constraints are also prevalent in the European Union.  Recently, European Researchers1 developed a validated method for the determination of […]

The Most Useful Pesticide Standard Ever…monitoring GC inlet “dirtiness”

I have spent most of my time over the past several years testing pesticides and there is one standard that I simply can’t live without…QuEChERS Performance Standards Kit. It is based on a really interesting article* on analyte protectants with a few compounds added. The standard has 40 compounds housed in three vials for long […]

You want them, I got them…a lot of them: pesticides GC-MS/MS transitions

I can tell you that determining transitions (SRMs) for GC-MS/MS can be quite challenging with so many precursor ions to evaluate. I spent a considerable amount of time optimizing transitions for our GC Multiresidue Pesticide Kit which has 203 compounds. That is a lot of transitions to evaluate! I also tested my chromatographic method for […]

New Restek EU PAH 15+1 Standard Separated on Rxi-PAH GC Column

Many of you may know that Restek recently developed and released a standard to support the determination of certain polycyclic aromatic hydrocarbons (PAHs) in food because they may be genotoxic and carcinogenic to humans.  You can find details on the EFSA Scientific Opinion that lists the so-called 15+1 PAHs here.  Hopefully you also know that […]

Easy Peasy: Optimized LC-QTRAP Method for Pesticide Residues

Despite what is sometimes advertised, setting up optimized methods for multiresidue pesticide analysis is typically not “easy peasy” and can be quite time consuming. Luckily, some colleagues are willing to share their method with us. Thank you Kelli, James, and Jon!* The downloadable spreadsheet contains retention times, transitions, ionization and collision parameters for our LC […]