Archive for the ‘Food’ Category

A closer look at selectivity and tailing: Essential oils and Wax phases

The most common way to analyze essential oils is to use GC with either a FID or MS. The wax-based columns are the number one choice for many users and following up on an excellent blog post by Corby, I wanted to evaluate two wax in Restek inventory: Stabilwax and Rtx-Wax. The essential oil we chose was […]

Falling Victim to One of LC’s Classic Blunders: Mismatching Your Diluent and Mobile Phase

An early lesson most of us learn in liquid chromatography is this: Always match your diluent to your mobile phase.  Once the exams are done, if you learned this in a college course, or your manager has walked away, you start flexing this “requirement” a little to see how matched they really need to be.  […]

Determining Optimal LC-MS/MS MRMs: Sensitivity is NOT Everything!

LC-MS/MS using electrospray ionization (ESI) is a widely used platform for routine target analysis and quantitation. However, one big challenge faced through the use of ESI is the presence of matrix effects. So, what are matrix effects and why are they important? Simply put, when matrix components coelute with the target analytes, they have the […]

Analyzing orange: peel and pulp separately or as whole?

Up to this point, I’ve focused on the optimization of QuEChERS salts and dSPE cleanup with fairly homogenous matrices. So, what about oranges? Should I peel them and analyze only the pulp? After all, that is the edible part. The peel is used as well – pressed into essential oils or scraped into zest. Besides, […]

Thrive with the New Rxi-65…TG!

Introducing our new and improved GC stationary phase: The Rxi-65TG! This column is essential for analyzing triglycerides in edible oils! You may be asking yourself, why the need for a new 65-type phase? Well, we certainly were not happy with the way our current Rtx-65TG was performing. After redeveloping the polymer and using Rxi technology, […]

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 […]

A Hoppy Little Story

Now that we’re getting into the warmer months of the year, you’re probably starting to see pop-up beer gardens or people outside relaxing with a nice cold one. Since the beer industry has been evolving and people are enjoying craft beers more and more, there are tons of unique brews on the market. If you […]

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 […]

Choosing the right dispersive SPE for GC-MS/MS analysis of celery

I’ve recently started experimenting with QuEChERS extractions for pesticide analysis. The available options are overwhelming, especially when it comes to dispersive solid phase extraction (dSPE) for the cleanup. For starters, I’ve been looking at the smaller volume dSPE (2 mL, summarized in Table 1), because I didn’t want to waste the raw material, solvents and […]