Archive for 2018

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 […]

VMS for when your TO-15 air lab is hazy, hot, and humid!

When it comes to analyzing volatile organic compounds (VOCs) in air canisters, it is no secret that my go-to-column is the VMS. I have raved about the VMS in the following pieces: The NJDEP-SRP Low Level TO-15 blog series My Favorite Column blog A white paper And some other articles I am forgetting… You get […]

How to Determine the Size of 1/4” and 1/8” National Pipe Thread tapered (NPT) Fittings

Restek’s Technical Service team gets quite a few questions from customers about fittings. There is a bewildering assortment of fitting types and sizes as you can see here on the Restek web site. A blog post titled, “I need a fitting, but which one?” is where we often direct customers for help with these questions. […]

The main source of artificial trans fatty acids is banned on June 18, 2018. Are we ready?

One of the leading causes of deaths in the world is heart disease, accounting for approximately 24% of deaths in the USA in 2015.1 One of the factors linked to cardiovascular diseases is consumption of artificial trans fatty acids (TFAs). Artificial TFAs are a by-product of partially hydrogenated vegetable oils, which were introduced as a replacement […]

Stabilwax Pro-EZGC Library Updated

Recently I blogged about the expansion of Rxi-624 EZGC library, this time I want to focus on an update of Stabilwax. At 462 compounds, this library covers the most searched, such as methanol or xylenes, and requested compounds, such as acetic and formic acid.* Similar to my last blog, I’d like to show you a […]

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 […]

A better way to configure your EZ No-Vent GC-MS Connector Part II

Last time, I wrote a blog (here) that showed a better way to configure the EZ No-Vent in the software so that the column length didn’t need to be manipulated. I kept the volumetric flow the same, and showed different ways to minimize the negative chromatographic effects of the reduced linear velocity. Today, I’m going […]