NJDEP-SRP Low Level TO-15 Series: Part 2 – NJ requires a specific set of 63 VOCs

As discussed in previous post titled Method TO-15 Requirements - Part I: "There's more than one way to skin a cat", the U.S. Environmental Protection Agency (EPA) Method TO-15 is applicable to a subset of 97 VOCs that are from the list of 189 hazardous air pollutants (HAPs) included in Title III of the Clean Air Act Amendments; however, only a few laboratories are analyzing all 97 components. Most laboratories are evaluating what I refer to as the standard suite of 65 volatile organic compounds (VOCs) for TO-15. Some researchers add in an additional compound or two (on top of the 65 that is), but again for the most part everyone is looking at approximately the same 65 analytes. NJ has decided on the 63 VOCs found on pages 34 to 35 of the method, which requires the use of the standard 65 VOC suite and 10 extra VOCs.

So first things first… right? We need to concentrate the aforementioned VOCs and shoot them onto our GC-MS. To accomplish this, I utilized the Markes CIA Advantage and an Agilent 7890B-5977A GC-MS with the following parameters:

With the aforementioned parameters I injected 250 mL of a 10 ppbv mix and we get the following separation of all 75 VOCs:

As one can see from the above total ion chromatogram (TIC), the 79 VOCs (every run includes 4 internal standards) are separated well in a 22 minute GC run. The only critical coelution found was for chloromethane and n-butane; however, we will discuss the significance of this coelution during the next installment of this blog series, which will cover calibrations. Note: I did not do anything fancy with the GC oven program, as I more or less started off with a Speed Optimized Flow and Optimal Heating Rate program.

The above TIC does not do justice to how well the Markes CIA Advantage and the Rtx-VMS are trapping, desorbing, and seperating these VOCs, so I have included the following extracted ion chromatogram for ethanol and isopropyl alcohol:

Anyone with some VOC experience can testify to the fact that the above EIC of ethanol and IPA is just plain awesome! So, mission accomplished. We have successfully concentrated and separated the compounds required by NJ (plus acrolein and napthalene, because we can). Stay tuned for next time, when I will talk about calibrating for NJ LL TO-15, which oddly enough... can be tricky because the method stipulates that most of the VOCs have to be calibrated from 0.2 to 40 ppbv.