Question: Have you used the bucket air sampler or other grab sample tool?

@jjcreedon, thank you! Are you still using buckets today? I'd love to hear more about your experiences. I've been reading up on Tonawanda Coke and Citizen Science Community Resources, it's really inspiring to hear about success stories like this! I'd also be interested to hear about follow-up soil testing and remediation work you've been doing since the plant closed.

If you're open to talking to me about this project, I'd love to set up a time to chat.

@Ag8n gc/ms is the standard way that bucket samples have been analyzed in the past, but it's expensive compared to the cost of the bucket. I'm familiar with this methodology a little bit -- as in, I have seen diagrams of how mass spectrometers work-- but I'm not a chemist and have never run these types of samples myself. Is gc/ms typically used as a standard method for air sampling? Looking at the EPA's market research for consumer air sensors, it looks like this is not actually a super common way of analyzing VOCs.

VOC just tells you the amount of volatile organic carbon, not the specific molecule. If the voc is all octane, that's a totally different situation than if the voc is all benzene.

Then the question is how do you identify each individual voc? The typical answer is chromatography. But then the only way you can match is based on retention time. There are situations where different molecules can elute at the same time. Look at court cases, for examples. So an extra form of identification is needed. This form of ID is usually mass spectrometry(MS).

It doesn't mean all samples need to be run by MS, but if they need to hold up in court, MS is probably needed.

Is GC-MS still typically done in a lab or are there versions that can be done in the field?

My question is really about current workflows for gas chromatography / mass spectrometry for environmental monitoring. Part of what we are trying to do is evaluate current options for testing grab samples, with the goal of sharing an updated resource list of labs that will perform gc-ms for community groups using the bucket. In my research so far, it looks like 1) most gas phase sensors that the EPA is looking at aren't even using gc-ms for testing, but at the same time 2) gc-ms is commonly used as an option for environmental monitoring, including tools that can be used in the field for forensics and emergency response (which sounds, at a minimum, like maybe things have become more cost-effective? that would be a big deal, sample analysis is expensive)

TLDR: I'm trying to get a handle on gc-ms is used for air sample analysis and the workflows involved. I'd love feedback on either question!

Ok, it's a question of the process and how much you know about it. If you know everything that's likely to be produced in a plant ( say a refining operation), you wouldn't need to do gc/ms analysis. There are usually much cheaper instruments that will give good info. That said, gc/ms might still be done ( say yearly) to make there was no major change.

On the other hand, in a n emergency response, you may have no idea what substance is involved. Gc/ ms maybe the best and fastest way to get the information.

As far as I know, gc/ms is still a lab operation. Having said that, gc/ms, lc/ms, and flash gc prices have been trending downward in the last few years. The size is also getting smaller. A portable version could be on the market.

Just be careful. Mass Spec can be touchy. Be sure to get a lot of info before committing to anything.

Here's a portable GC, but has a TCD detector.. not the same. https://www.agilent.com/cs/library/brochures/5991-6041EN.pdf No GC/MS portable unit. It can get pretty complicated and would need a seasoned analytical chemist to explain all the possible detectors that can be used with a GC.. it really depends on the application. The Bucket has been the standard tool in EJ work, because it is portable and easy to use.

The TCD is a thermal conductivity detector. It's an attempt at a " universal" detector- that is one that will detect most substances. The problem with the TCD is that it isn't very sensitive.