Pesticide in Lavender oil

[sky]

I got a great matrix interference in examination of pesticides (organochlorine & pyrethroid) in lavender oil from GCECD and GCMS. I tried several SPE cleanup like alumina, silica, florisil etc, but still see that huge mountain in the chromatogram.
Can anyone who have experience on this problem share their opinions to me?
When I do it in lemon essential oil, silica can do well.

[L4br4t]

Have you tried running the samples through a GPC?

[Rick]

psa AND gcb

[WK]

Hi Sky,
Please can I ask how you do the clean up? Do you just pass the essential oil through and collect the elluent?
I am collecting information in this area generally at the moment.
I have not found much on column clean up of essential oils.
I have problems in this area with lemon oil too.
WK

[sky]

Well, I had tried to do it by GPC, Floirisl, GCB & Silica, but still go the matrix interference.

Outcome:
1) Still see many peaks in the Chrom.
2) Poor recovery (below 50%)
3) Still retain the oil texture after cleanup, so can't dry it.
4) Need to change liner rapidly, even the column.

For lemon oil, I think either silica or florisil is fine.

You may try to treat the sample by conc acid if your analytes do not destory by it.