Archive for the ‘Miscellaneous’ Category

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 […]

Rxi-624Sil MS Pro-EZGC Library: 591 Compounds to Choose From

Five years ago Chris English showed in his blog post “I Can’t Drive 55” — The Pure Power of EZGC all 233 compounds that were in the Rxi-624Sil library. While that is a lot, we didn’t want to stop there. This weekend we added over 350 new compounds with various functionalities – e.g. alcohols, aldehydes (first time […]

Optimizing Mass on Column to Balance Sensitivity Requirements and Calibration Range with Split Injection

This is a continuation of the EPA Method 8270 blog series started in January of 2016. Previous posts: 1, 2, 3, 4, and 5. We’ve been focusing on the advantages of split injection analysis, while highlighting the weaknesses of splitless injection. This blog is going to revisit the topic of column overload in more detail […]