EPA method 552.3

[haslani]

Hi All,
I am trying to calibrate my GC ( Varian CP 3800) for HAA5 using EPA method 552.3. I could develop calibration for all elements except DBAA. I could not find the exact RT for this element, do any one has an idea solving this problem? Our GC is coupled with column DB 1701, and ECD detector. I followed the method step by step several times, but the problem still remains.
regards

[kubowicz.tomasz]

Hello

I could not find the exact RT for this element
regards

What does it mean? Did you try to inject only DBAA and compare retention time with standard mix?


Regards

Tomasz Kubowicz

[haslani]

I did it alone, and the RT was the same as other element i.e. TCAA, how can I separate these two, when both are in the matrix.

[whdees]

we have seen this problem also. you can try a column with a different polarity stationary phase, that might separate them.

[Bigbear]

We do 552.2 and our confirmation column has a co elution with this compound The method states dual columns need to be used.

[CharliesMom]

Hi Bigbear,
So, must a dual ECD and column to run EPA 552.2?
I heard about a “highly recommended”. I looked it up in the method... and there it was section 1.4

I would think clarity by using the wording “ must” on this would be very helpful???
Hope you can reply!!!

[Steve Reimer]

An alternative to dual column, dual ECD is to analyze using one column, swap it out and analyze with the other for confirmation of hits. Or have separate instrument with the confirmation column. Not the best solution but possible. Thus, the 'highly recommended' rather than must.

[James_Ball]

We use the Restek CLP and CLP2 column pair and the analytes separate well on both columns. The other column to try would be a 5 phase like Rtx5 or DB5 and see if that separates them.

[sgibbons20]

Hello all!

I know this post is a little old, but hopefully I can get some kind of response. I am currently developing the EPA 552.3 method, and have a question about the method. This was the only forum that popped up when I searched this method on this website.

The question I have is about doing a dilution, in the method it states that I can dilute the extract with the MTBE with the internal standard. When I run the diluted sample how would I account for the increased concentration of the internal standard? Or would the increased concentration not even make a difference if for example I do a 1:3 dilution with a final volume of 0.6mL?

Or is it assumed the Internal Standard concentration wouldn't increase at all because the MTBE solution stays the same throughout the extraction process?

Thank you in advance for any help given!

[70 eV]

There isn't one. The IS should come back with close to the same response, you just can't use the surrogate data off the dilution.

I am curious about Jame's method for the CLP columns. I'm running 1701/5.625 and I've got a garbage coelution on MBA with the 5.625. We recently validated 505 on the CLPs and I'm interested in getting 552, 504, and 515 onto the same column pair.

[James_Ball]

I haven't done 504 on that pair but all the others work. I think in 515 you may have a close elution of a few on one column that do resolve on the other. If you can't get 515 to work on the CLP pair then you can try a 5 phase and a 35 phase, those seem to work ok, but one will have a longer retention time for the final peak than the other by a few minutes.

For 552.3, if you are diluting with the extraction solution that includes the internal standard, it concentration should not change for the internal since you are diluting with a solution that is the same concentration as the sample is, as mentioned the surrogate will be lower by the dilution factor so a 5 dilution would make a 10ppb surrogate into a 2ppb ect.

It is actually one of the good things about the 552.3, you don't need to figure out how much internal to add to the diluted sample to compensate for the volume of diluent.