Tetraethyl lead by 8260

[rv3]

I've been tasked with developing a process for Tetraethyl lead by 8260B and the only information i can readily find uses ICP/MS. Is there anyone with experience in this? Specifically wondering about the soil extraction process, we typically use MeOH as preservative and draw an aliquot from there. Most of what i've seen is SPME and headspace analysis, which is not an option for us. I did find an earlier thread here viewtopic.php?f=3&t=19788&p=94811&hilit=lead+tetraethyl#p94811 that didn't really have any information in it. Thanks in advance.

[James_Ball]

I don't see it listed as an analyte in either 8260 or 8270. Molecular weight at 323amu would put it near the top of the scan range for 8260, around the mid range for 8270.

I found one procedure where it is extracted with Hexane and direct injected, which would make it seem to be more of a semi-volatile than a volatile compound. There were also some references to purge and trap gcms used for tetraethyl lead but those were all Chinese publications.

You would need to check the solubility in methanol before using that as the injection solvent if you will extract it, but it is definitely soluble in hexane and I imagine other non-polar solvents would work as well, just not sure how well methanol would work with it being more polar.

It would be something you would just have to try and see how it works, but be very careful with standards since it is such a highly toxic substance and very volatile as well.

[Yama001]

We do this occasionally using SW846 8270. It works fine as an extractable analyte.

I would think 8260 will work as well, though I have seen some really odd behavior with the heavier Alkanes in a Purge and Trap (PIANO analytes). James make a good point regarding methanol solubility.

[rv3]

We do this occasionally using SW846 8270. It works fine as an extractable analyte.

That was my suggestion when it came to me was to do as James noted (and most seem to agree with) is running it through 3550 extraction with Hexane and DCM and do a direct inject. But that got shut down from higher up the chain. I don't think the water P&T will be too much of an issue. It's the soils that are a bit concerning. One major mass fragment is 237 m/z so it is within the top end of our scan range (Barely).

I don't see it listed as an analyte in either 8260 or 8270.

It's isn't listed for the EPA, the Arizona DEQ is looking for it as part of their risk assessment.

Thanks for the input, looks like good ol' fashioned trial and error it is. I'll make updates when i can to save anyone else that needs to the hassle.

[AICMM]

If I am not mistaken, used to be done with an ECD to quite low levels. I will dig into my notes and see if I can find reference to such.

Best regards,

AICMM

[mckrause]

We ran all of the ethyl leads, from mono through tetra, in SIM using essentially 8260 conditions. It works quite well and is very, very sensitive if you tune your system correctly. I got my standards from Aldrich (this has been a while ago). You get nice, clean ions - none of the normal interferences. I still occasionally use it for fingerprinting PSH, but of course the leaded PSH is rare now.

[danicrd]

We ran ethyl and methyl species with 8260. Be aware of system activity and trap, we experienced some problems with recovery and often the problem was in analytical trap. We used tekmar systems. I'm curios about condition to reach "mid ppt" i've seen on another post, actualy (on water) we are at about half ppb with sim/scan acquisition: I think ms sensitivity is not a concern to lower detection limit
Thanks

[rv3]

Hello again,

Thank you for your input, we've done some very preliminary runs and so far it doesn't look great. We ran a few tests at our Calibration Midpoint level of 25 ppb. I'm having some issues uploading the chromatogram but the TEL was recovering with an area of about 2% of the nearest internal standard and tetramethyl lead recovering at around 22% of the area of the nearest ISTD. Given that and the general noise in the area i'm looking at a lowest reasonable reporting limit of about 10 ppb for TEL and maybe 1 or 2 ppb for tetramethyl lead. This is about 1000x higher than what's desired. As was said here:

If I am not mistaken, used to be done with an ECD to quite low levels.

seems to be the way to get the really low level stuff. Is there anyone with some sense of where the P&T is capable of going,as far as low level?

[rv3]

Further update. I built a SIM method on Chemstation and we're getting solid recoveries down to 0.1 ppb fairly easy. The linearity is really good as well. at this point i'd say it is done. if anyone else is trying this go for a SIM method. due to the difference in retention time i have 2 internal standards and surrogates that we were already using for the normal scan 8260.

[LALman]

Further update. I built a SIM method on Chemstation and we're getting solid recoveries down to 0.1 ppb fairly easy. The linearity is really good as well. at this point i'd say it is done. if anyone else is trying this go for a SIM method. due to the difference in retention time i have 2 internal standards and surrogates that we were already using for the normal scan 8260.

I've just had a customer ask me about this. I have an Agilent 5973 inert MS with fast SIM/scan capable. This is amenable to purge and trap then?