Archive for the ‘Tips & Tricks’ Category

Chemical Reference Standards: Don’t Just Snap and Pour (Part 2)

Several years ago, my colleague, Alan Sensue wrote Chemical Reference Standards; don’t just snap and pour. In it, he described a personal experience where he mixed several expensive reference standards together assuming the vials contained exactly 1 mL. It was a mistake he has remembered for some time. Here are a few other examples as […]

Troubleshooting GC Column Baseline Issues

Every GC analyst experiences baseline issues at some point in their career, whether the baseline is higher than normal, or it contains additional peaks/spikes, or becomes erratic and drifts up and down.  In order to fix the baseline issues you will need to determine the cause.   I hope that the information contained in this post, […]

Using EZLC to adapt an LC pesticide method for lower pressure

  Our most popular and successful LC column for the broadest range of pesticides is the Raptor ARC-18 column. We are able to retain, provide good separation and peak shape even for many of the more polar pesticides. Whether your matrix is a food, agriculture crop or a cannabis product, the Raptor ARC-18 will probably […]

Solid Phase Extraction: Separation is the Foundation of this Preparation!

In a previous post, we made the case that the foundation for analytical separations is sample preparation.  In this post, we would like to talk about how it works the other way around, too!  Separation can actually be the foundation for sample preparation.   In particular, we would like to talk about how solid phase extraction […]

Modifying QuEChERS for complicated matrices- Soil and Sediment

In previous blog posts for this series on QuEChERS, we discussed QuECHERS dSPE Selection, Modifying QuECHERS..-Dry Samples, Modifying QuEChERS..-High Fat Samples, and Modifying QuEChERS..-High Sugar & Starch. Once again, I suggest using the following documents from the official QuEChERS website (, maintained by CVUA Stuttgart: For Extraction (Stage 1): For dSPE Cleanup (Stage 2): […]

Potency: Useful Techniques

The most labor-intensive part of determining the potency of samples containing cannabinoids is extraction. Due to a plethora of matrices, from candy, baked goods, lotions, and so on, selecting the most suitable extraction method can also be a challenge.  The following video and technical article will guide you through that initial process: How Potent is […]

Not Every Matrix-Matched Calibration Is Made Equal – Case of Spinach

Matrix-matched calibrations are a popular option for complex matrices, such as food commodities. When it is employed, one can assume that the majority of matrix effects will be accounted for and there won’t be much difference between calibration standards and the tested samples. But are all matrix-matched calibrations equal? In the case of QuEChERS extraction, […]

Short Webinar on Calculating Column Length Using EZGC Flow Calculator

Determining the length of your GC capillary column is essential for accurate control of carrier gas flow rate.  Just because you purchased a 30 m column, does not mean that your column is exactly 30 meters long; in fact, columns will typically have a little extra tubing.  But ultimately, it is not the physical length […]

Derivatization techniques for free fatty acids by GC

Anyone who has tried to analyze free fatty acids by GC realizes they have to derivatize these compounds. The inherently low volatility of free fatty acids and the carboxylic acid (-COOH) interaction with the siloxanes in the stationary phase. If not addressed, the first problem leads to late-eluting peaks and the latter results in peak […]

Getting Your LC Up and Running Again

Welcome Back!  You and your lab have been through a lot these last few months and now it’s time to get your LC back up and running.  After it has been down for a few months, it likely needs a little TLC before it’s performing optimally again.  Just like a car that sits around for […]