Endrin Aldehyde loss in 8081

[stevepruskin]

I have an intermittent problem seeing Endrin Aldehyde in extracts, spikes, LCSs and DCSs by method 8081. No problem with my standards, so it's something in the extraction procedure. Sometimes it's low in water and good in soil, sometimes the reverse. Water extraction by sep funnel, soil by ASE. Sometimes there's a visible drop in baseline in blanks where Endrin Aldehyde should be.

My guess is some contaminant is co-eluting and suppressing the signal, but I can't imagine what it could be. I've checked the common phthalates and they don't co-elute with it. All the other 8081 analytes are fine. Just this one and it comes and goes with no obvious pattern.

Has anyone else seen this, and I hope solved it?

Thanks.

[dalarie]

I know you posted this last year but I am wondering if you still have the same problem. I am seeing the exact thing in my water samples. It doesn't occur in solid samples. If I send the spikes for florisil column clean up, the endrin aldehyde comes back. It is in the extract but it is not coming off in the chromatography.
Just today I revialed a spike from the original extraction tube (first run got 40%) and the result was 100%. I have no idea what is going on?

[8jw8]

is it possible that you have a contaminant peak incorrectly identified as endrin aldehyde?