[azoxystrobin]

I am having trouble with solid phase extraction and was wondering if anyone could help.

All I seem to get so far, is that SPE is empiric (translate that as - trial and error)
I'm not too keen on trying out millions of possibilities and wasting so many expensive cartridges.

anyway, I have an extraction mixture (which should include my organophosphorus pesticides) in cyclohexane, and would like to clean it up through an SPE cartidridge, now usually C18 cartidges are used, but C18 seems to be used with methanol or acetonitrile.
another paper has used florisil cartridges, but i've heard elsewhere that there is analyte loss with florisil.

so could i put cyclohexane through a C18, and would it do anything?
if i really must use cyclohexane, how should i prepare the cartridge?
what would be a good eluant?
is this the right place to post this kind of question anyway?
thanks in advance

[chiralic]

Hi...You must read this, I found it on internet:

http://www.epa.gov/sw-846/pdfs/3535a.pdf

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400012

Are you using AOAC Method or FDA Methos or EPA Method or FAO Method to extract your pesticides?
What is your matrix?

Regards

Chiralic

[azoxystrobin]

Thanks for the info, nice find.

I don't know what your acronyms mean!
EPA? AOAC?

well I should be using european normalised methods, NF EN 12393 and possibly NF EN 1528
But they aren't very efficient methods.
So i'm looking to optimise those methods.

The matrix is wheat, but I should be working on more complex stuff, like other crop cultures and oils.

I could do with finding a very rapid screening method too, at the moment I'm thinking about SPME, I've used it before to detect pesticide residues in strawberries, it's very efficient when compared to archaic liquid/liquid extractions.

Any further advice on this kind of thing would be welcome
cheers