Author Archive

Preserve your SRM transition windows by replacing the same amount of column you remove during maintenance

I’ve been working on a detailed PCB congener analysis using the TSQ-9000 with the AEI. Typically this analysis is done by EPA Method 1668C, which uses high resolution MS. We get some specificity from the selected reaction monitoring, but there are some shortcomings when compared to high resolution data. Where the TSQ-9000 really shines is […]

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 […]

Pro EZGC Update: Comprehensive 209 compound Library of Brominated Diphenyl Ethers and a New Column Format

While attending Dioxin 2018 in Krakow, I noticed that several academic researchers were studying  the toxicity of specific PBDE congeners not on the standard target compound list for EPA method 1614 (or the EU equivalent). Though PBDE mixtures have been phased out of production and use, the concentrations in the environment have not been declining […]

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 […]

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

If you are using the EZ No-Vent for Agilent mass spectrometers (cat.# 21323), you are probably tricking your instrument into working properly by inflating the length of your column in your acquisition software. If you have MassHunter, or a recent version of MSD ChemStation  (G1701EA), you don’t have to do this. Instead of configuring your […]

355 compounds have been added to the Rxi-XLB library for the Pro EZGC Chromatogram Modeler

The Rxi-XLB is a popular column for the analysis of PAHs and persistent environmental pollutants (POPs) such as PCBs and Pesticides. We’ve updated the library of 209 PCB congeners, expanded the PAH library to 47 compounds (including 6 deuterated isotopologues commonly used as internal standards or surrogates), and added the 203 compounds in the GC Multiresidue […]

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 […]

Upcoming revisions to three wastewater methods reviewed at NEMC 2017

Monday morning, representatives from the EPA’s wastewater office reviewed the significant changes for the three major GC wastewater methods: 608.3, 624.1, and 625.1. The overarching goals were to modernize the methods and bring the language and QC requirements in line with the methods from the drinking water and hazardous waste offices. The methods have been […]

Troubleshooting Injection Volume Variation in the Concurrent Solvent Recondensation – Large Volume Sample Injection Technique

I’ve started receiving a number of questions about the large volume injection technique called Concurrent Solvent Recondensation – Large Volume Sample Injection. Most recently, a question came through the Tech Service group about injection volume variation. I had encountered a similar problem when working on the 50 µL injection for the combined 1,4-Dioxane and Nitrosamines (EPA […]

New Custom UCMR4 Standard for EPA Method 530 on the Rxi-5Sil MS

We recently stocked custom EPA Method 530 standards made specifically for labs participating in Unregulated Contaminant Monitoring Rule 4 (UCMR4). Quantitative Certificates of Analysis with Data Packs are available for each item. Contact Customer Service to place your order (items are not available at Restek.com). EPA Method 530, the Determination of Select Semivolatile Organic Chemicals in Drinking […]