[toxman]

Can someone explain to me what is meant by a "neat" standard curve or a "neat" preparation. Does this refer to a post extraction spike or no extraction at all? Please explain.
Thank you 

[Lorax]

I believe what you are refering to is a solution (or set of solutions) containing the analytes of interest and a solvent.  Contrast that with an extracted curve, which would consist of analytes of interest added to a matrix and carried through the extraction process.

In general, an extracted curve can help you overcome matrix effects in your samples, but an unexctracted curve is much easier to prepare.