Chromatography Forum

phthalates are a source of contamination, think it might be even mentioned in the method...

Yes, the EPA method indicates that pthalates is a major interference. I'll start using plastic falcon centrifuge tubes made of polypropylene, wich is considered to be free of pthalates. The maximun temperature during the derivatization is 50oC. Next week i''ll run a blank and a standard sample to find out if there is any interference. All these because it's quite difficult to find the same type of tubes mad eof clear glass.

I'll add my two cents here: have been running this EPA 552.2 for a few years now, and it is the curse of the department! Curves are usually linear (average RF), but my frustration has been the LCS/CCV/DOCs, which is prepped at the same time using the same chemicals as the curve, but fails to meet requirements. Surrogate 2,3-dibromopropionic acid is a problem as well, usually low. Ran a study on it, recovery was higher the longer it was extracted, the target HAAs are rather flat. Since then I have added the 552.3 surrogate 2-bromopropionic acid to samples as well, it is quite stable.

Using Restek CLP-Pest and Rtx-1701 columns with success, had coelutions with other phases. Does have the tendency to destroy columns.

The Kimble part number for the glass centrifuge tubes is 45166 15, I wouldn't fool with anything plastic in an organics lab.

Anyone have better success with 552.3? I haven't had the time to try it more.

When I ran that method I always used a quadratic fit. Also, I had to calibrate over an extended range and I actually split it into two methods - a low cal curve and a high cal curve (5 points each). My auditor was just fine with that.

I'm working on getting our lab certified for 552.3 and am having a devil of a time with monochloroacetic acid. Calibrations look good, performance samples pass, but most real-world samples seem to have a co-eluting peak at the same RT as MCAA (A & B columns don't agree, peak is slightly right of RT but w/o a shoulder, high quantitations). I think I have a solid instrument aquisition method for our PE Clarus 580 using Restek CLPesticides columns & have eliminated any sources of contamination as best as possible. Anyone else having this issue? Overall, the method seems to be working fine except for this. Anyone else seeing anomalies with MCAA in real samples?

When I ran that analysis I had problems with a co-eluting peak for MCAA on one of the columns, I don't remember if it was the CLPest1 or CLPest2. Of course, it is the lowest response peak.

Some new findings for the HAA analysis - I replaced my straight liner with a cyclonic double-gooseneck liner and may actually have achieved separation of MCAA and the co-eluting compound on at least one of my columns. I'm running a full calibration and QC to check the results. Anyone else here try different liners to solve their HAA issues?