Archive for the ‘GC/MS’ Category

Modifying QuEChERS for complicated matrices- Dry Samples

Before getting in to this discussion, I recommend reading my previous blog post first regarding classical applications for methods based on Quechers. https://blog.restek.com/quechers-dspe-selection-which-one-is-best/ QuEChERS methods were originally written to analyze pesticides in fruit and vegetable matrices, most of which have high water content and low fat content. More recently, the technique has been used for […]

Pesticides are like Siblings, They Don’t Always Get Along part 2 – now with the GC mix!

Last year my colleague Landon publish his blog about pesticide multiresidue LC mix stability in a celery matrix and in a solvent. Today, I’d like to show you what happens when you do this with the GC multiresidue pesticide kit. On day 0, I prepared stock solutions from all 9 ampules of the GC multiresidue […]

Cryogenic Cooling for Air Analysis Part 2 – Combining TO-15A and Ethylene Oxide

In my previous blog on cryogenic cooling (https://blog.restek.com/cyrogenic-cooling-for-air-analysis-interferences-from-n2-co2-and-o2/) I touched briefly on ethylene oxide (EtO) and why it may be of interest in ambient air analysis. While OSHA has a time weighted average (TWA) limit for EtO at 1ppm for an 8 hour exposure, recent work by the US EPA has shown that even low […]

Does the Amount of Wool in Prepacked Liners Matter?-Part II: Results

In Part I of this series, I posed the question of the impact of the amount of wool on liner performance.  As a reminder, this study specifically examines Topaz liners that are prepacked with wool and then deactivated. With your own hand-packed liners these results will not apply. The first criteria I wanted to examine […]

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 […]

Step-by-step instructions to easily, quickly and safely shut-down your GCs

In this current economy with stay-at-home recommendations/requirements due to the coronavirus, it has been unfortunate that many laboratories have been or will be forced to temporarily close their doors until the spread of the virus decreases enough that the stay-at-home orders are rescinded. If you find yourself in this distressing situation, sometimes it is difficult […]

Cryogenic Cooling for Air Analysis – Interferences from N2, CO2, and O2

Spring is already here and summer is just around the corner and soon we’ll be trying to stay cool.  For those of us doing ambient air analysis though, keeping cool can sometimes mean cryogenic cooling. While our VMS columns can easily separate the TO-15 compounds with no need for cryo cooling (see https://blog.restek.com/air-columns-part-iii-my-favorite-column-phase-for-epa-method-to-15/) there are […]

One Stop Shop for Essential Oils Chromatograms

In the past few months, we have collected a variety of chromatograms using two different column phases, and three different column dimension formats. The peak identifications were performed using some standards but mostly from the NIST MS EI spectra library, 2005 edition. Let us know what you think in the comments below. Citronella Java GC_FF1296 […]

Terpene Analysis Approaches – Part III

It’s time to dive back into analyzing terpenes! Previously, we looked at two types of sample preparation for analyzing terpenes via HS-Syringe and HS-SPME. If you missed those blogs, be sure to check them out here and here before moving on! In my last blog, I showed that HS-SPME outperformed the HS-Syringe when analyzing terpenes. […]

Discovering Analyte Breakdown On-Column

I completed my winter internship at Restek and my main task was to expand the Pro-EZGC libraries. So I created a library for Nitrosamines on the Rxi-1301Sil MS and while acquiring data we noticed a foot on a couple of my peaks. I attempted to translate the simulation to a column with the same phase, […]