Archive for 2018

Trans fatty acids analysis part 2: Let’s look at actual samples with incurred TFAs

In my previous blog, I’ve tried and failed to acquire a sample that contained any trans fatty acids (TFAs). While this is a great news for everyone’s health, the scientist in me was somewhat disappointed. That’s why I first decided to cheat a little bit and look at different TFAs – ruminant TFAs. Ruminant TFAs […]

What’s in a name? A C18 by any other name would not be the ARC-18

You have probably read or been told numerous times and in numerous ways that not all C18 columns are the same. And that is very true. Particle morphology, bonding chemistry, and add-ons like end capping all influence the retention and selectivity of this workhorse LC phase. At Restek we have an interesting C18 phase that […]

How often do I need to get my electronic flowmeter recalibrated?

The answer is it depends. It depends on how often you use it. It depends on the environment it has been exposed to. It depends on what your company’s, industry’s or government’s regulations on recalibration are. It depends on whether you have accidentally dropped or banged the device. It depends on how confident you are […]

The Chromatography Picture-Show

If you’re caught up on all your favorite shows, might I suggest the Restek Video Library for your next binge. Most of the episodes only run about two minutes, so there are few extraneous subplots. (And, so far, no car chases. Not a single one in over 50 videos! But new episodes are added all […]

Have there been any new applications developed for Diquat and Paraquat?

I am happy to answer “yes” to this question. Those of you who have been doing this analysis might have been using our Ultra Quat column that I talked about in an earlier blog post here, “I have an Ultra Quat column and I know how to use it…”   This updated method uses the […]

Which Headspace Vial Cap Is Right For Me?

Today, I’d like to cover a question that I have been receiving from cannabis labs who are doing residual solvents analysis. This blog may not only help cannabis labs, but also help labs analyzing other matrices looking for residual solvents or very volatile compounds. The question is, “Which type of vial and vial cap combination […]

Tailing solvent peak during split injection? Check your column installation distance!

When performing splitless injections, it is not uncommon to witness a tailing solvent peak, given the large amount of solvent introduced onto the column over a relatively long period of time.  For split injections, however, only a small portion of the solvent loads onto the column and it occurs very quickly. This results in a […]

Are My Shut-off Valves Contaminated?

Shut-off valves provide a convenient means to control gas flows and are often used in conjunction with gas chromatography systems.  There are several types of shut-off valves including ball valves, plug valves, and diaphragm-sealed valves.  Some of these valves, ball and plug valves included, use a silicone-based lubricant to make opening and closing the valve […]

The usage of Reference Standards in MOSH/MOAH Analysis

Abstract The unintended migration of mineral oil compounds into food, e.g from packing materials or from production processes are a raising topic in industry and scientific discussions. For a first screening, an LC-GC/FID method was established in the last years. In collaboration with Axel Semrau, Restek has developed ready to use standards for quantification and […]

Annual Replacement of Cartridge Gas Filters

A significant number of instrument and column complaints are carrier gas related, which could be caused by breakthrough from filters that are not replaced in time. The possible consequences of a filter breakthrough are: Gas distribution system behind the filter will be contaminated (fast cleaning nearly impossible, bleeds for months) Instrument gets contaminated, expensive maintenance […]