Huge Peak suppresses the recoveries of other peaks

[EnvChemist]

Hi all,

I am having a problem where a huge peak eluting at the center of my chrom is suppressing the recoveries of all my other peaks - including my surrogates. I am using MSD ChemStation to analyze PCBs, has anyone experienced this problem before and knows how to rectify it?

[AICMM]

EnvChemist,

In your blanks? In your LCS/LCSD? Just soils or soils and waters?

Sulfur?

Best regards.

[EnvChemist]

In just the samples - soils and waters. Initially I thought it was a sulphur peak and did some additional sulphur cleaning (we use copper powder), but that didn't help at all.

[Peter Apps]

First step is to identify the peak from its mass spec - knowing what it is will help design ways to get rid of it.

Peter

[EnvChemist]

We tried that and were unable to identify it ....

[AICMM]

EnvChemist,

Have you tried sulfuric acid/florisil cleanup? Did you do this to the LCS/LCSD as well? Could it be in a cleanup step that is not done to the LCS/LCSD?

Are the samples from the same customer/area? Is you copper turning color to suggest there is some sulfur in there? I found that copper did not work the greatest and had to be in really good shape to clean up the sulfur and even then it did not work nearly as well as mercury.

Just out of curiousity, did the mass spec show a peak/hump at all and do you have a spectra?

Best regards.

[Uwe Neue]

Humic acids fit such an event. Check on the Waters webside on the Oasis packing for tricks to get rid of humic acids. Currently, I can't give you more info, since I do not know your sample prep.