Archive for the ‘Troubleshooting’ 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, […]

Troubleshooting 101

Like most folks who work in the lab, you likely have had some downtime in the lab due to various reasons, like a column, instrument, sample prep, standards, and even application or method conditions. Troubleshooting then commences. Details are often needed, in order to get the bigger picture. One of the most important troubleshooting tools […]

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 […]

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 […]

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 […]

Did you know you can manage jagged bleed with a controlled cooling program?

GC column bleed sounds like one of those old problems people used to have. The XLB was developed to lower detection limits by minimizing bleed. Now, virtually all polysiloxane GC columns are low bleed, with thick film and high polarity phases being the exception. Modern GC-MS instruments are so sensitive that I’m rarely concerned about […]

How I clean a GC injection port

Recently I have been asked by several customers how to clean an injection port.  My initial answer is always the same, you should clean the injection port according to the manufacturer’s recommendations.  But what instructions do I provide when the injection port was manufactured by Restek?  I usually provide the same response but then I […]

Are PFAS sticking in your system?

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in our society and can be found in a wide range of consumer products; hence they are widely present in the environment, people and animals. They are persistent chemicals that have the potential to accumulate. Therefore, they are evaluated and monitored using a variety of methods and controlled […]

Purge and Trap weldment installation

Sometimes we get asked by customers for clarification when installing/connecting a new or replacement weldment from their purge & trap autosampler to their Agilent GC’s split/splitless injection port. As a result, I wrote this post to assist those that may be new to this type of installation or those that simply could use a quick […]