552.2 surrogate

[Bigbear]

We just installed a new DB-XLB column with 1 um film (needed as we also use this instrument for 515). Now we do not have resolution between the 2-BPA surrogate and the "system blob".
Does anyone use another surrogate for this method?

Thanks
John

[James_Ball]

I spoke to our analyst and he said we are using the Restek CLP Pest 1 and CLP Pest 2 column for both 552.2 and 515 analysis and we use 2,3-Dibromopropionic acid without any co-elution problems. I believe though that we reference 552.1, not sure if 552.1 allows for that surrogate but I believe 552.3 does allow for alternate surrogate compounds. We use that column pair for most of our GC/ECD analysis.

[Bigbear]

Thanks, the 2,3-DBPA elutes late on our columns, but no where near any other compounds.
How does 552.3 work for you James with regard to the IS recovery? We have lots of variability in response adding the IS post extraction.

[Jesse Robinson]

Hello,

We have been analyzing HAA's for many many years. Adding the internal standard post spike works very well for us. The internal standard we use is 1,2-Dibromopropionic Acid. There are no interference's in our samples or standards so when added post extraction we get very consistent results. It's important to use the appropriate syringe for this application however. We add 10uL of IS to 1.0mL of sample in an auto sampler vial using a 25uL Hamilton syringe.

I work with James by the way.

[Bigbear]

That's how we do it as well but we 123 TCP. I would rather have the IS in the extraction solvent per 552.3. I wonder if TCP would hang around with all the extraction manipulations.

[James_Ball]

1,2,3-TCP has a boiling point above 150C so compared to the extraction solvent it is much higher and the extraction solvents should evaporate first. As long as it is completely soluble in the solvent it should be ok, but I would run a set of blanks through the extraction process and compare to a non-extracted blank just to be sure.

[Jesse Robinson]

Does your IS vary only in samples or is it inconsistent in standards as well? If it is present only in samples, then I would suggest running some "real world samples" through the extraction process without adding internal standard. Analyze these extracts under normal conditions and see if there could potentially be an interfering peak present where 1,2,3-TCP should be. I have seen this many times when attempting to use this internal standard.