Seven EPA Methods – One GC Column Pair! Are You Serious?

As I’ve been traveling around talking with environmental chemists I’ve heard them say more than once: “Why can’t there be just one GC column set that will work for a whole bunch of methods instead of having to change columns to run a variety of methods?”

Changing columns can be time-consuming and frustrating for a pesticides chemist working with GC/ECD methods, especially when there are large backlogs and deadlines to meet. Dedicated instruments are not a suitable answer since equipment utilization is so critical and some methods are not run routinely. An Environmental Innovations chemist at Restek may have a solution.

A recent discovery by one of my colleagues at Restek, Jason Thomas, answers this question. Jason surveyed how many EPA methods he could run using a single set of Rtx- CLP and Rtx-CLP2 columns on the same GC/ECD instrument. To my surprise it came out to seven EPA methods!

He gathered chromatograms for EPA methods 8081B, 8082, 8151A, 504.1, 505, 508.1 and 552.2 and found that they could all be done using a single set of application specific columns for multiple GC/ECD methods.

Here’s a summary table showing the specifics of his survey:

EPA Method	Column Pair	Analysis Time (min.)	Coelutions	Link to Chromatogram
8081B Chlorinated Pesticides	Rtx-CLPesticides/ Rtx-CLPesticides2	7 / 7	0 /0	GC_EV00933
8082A Aroclor PCBs	Rtx-CLPesticides/ Rtx-CLPesticides2	7 / 7	0 / 0	Aroclor 1221 PCBs on CLP Aroclor 1221 PCBs on CLP2
8151A Chlorinated Herbicides	Rtx-CLPesticides/ Rtx-CLPesticides2	13 / 13	1 / 0	GC_EV00971
504.1 EDB, DBCP, 123TCP	Rtx-CLPesticides/ Rtx-CLPesticides2	9 /10	0 /0	GC_EV00020
505 Organohalide Pesticides & PCBs	Rtx-CLPesticides/ Rtx-CLPesticides2	18 / 18	1 / 1	GC_EV01004
508.1 Pesticides & Herbicides	Rtx-CLPesticides/ Rtx-CLPesticides2	23 / 24	2 / 2	GC_EV01022
552.2 Haloacetic Acids	Rtx-CLPesticides/ Rtx-CLPesticides2	12 / 12	0 /0	GC_EV01006

 

I noticed a couple of things as I looked at the chromatograms in this table. Not only can this many EPA methods be run on this one column set, but the resolution using the GC conditions indicated minimizes the number of coelutions for each method and the run times are optimized for fast analysis.

I’m glad to say that additional information will become available soon on a new “micro site” that will contain additional data and information about this surprising discovery. Keep checking this BLOG site for more details.