Cryosectioning for mass spec analysis..HELP

[philliesfan]

Hey guys,

I was just wondering if anyone had any experience in sectioning tissues for mass spec analysis? I have several different types of mouse tissues I need to section for mass spec analysis: brain, spleen, liver, intestines, heart, and kidneys. I have come across some interesting challenges. The first challenge, for mass spec analysis I need to section larger tissue sections >50 microns. I have tried TissueTek OCT compound; however, I have read that it will suppress ion signal. The second challenge, I cannot dehydrate the tissue in any way. So sticking the slide in 95% Ethanol after sectioning to clear the OCT compound, is not a possibility. Also, infiltrating with paraffin is an absolute out. I have been doing some digging trying to find non-polymeric embedding methods. Does anyone out there have any experience/suggestions in the following:

1) Ice slush - I'm not quite sure what exactly this is - a few publications referenced this method but I am assuming you either freeze the tissue in a block of distilled water or use the water as a "glue" to adhere the tissue to the chuck? Which I can imagine will lead to really bad freeze artifacts.
2) 10% Gelatin - it seems to have almost the same consistency as the OCT when frozen.
3) 2% aqueous carboxymethyl cellulose embedding media (Sigma C4888).
4) Cutting without any embedding media and maybe using the OCT as a "glue" to glue the tissue to the chuck - which I can imagine is going to be as fun as it sounds (especially brain). If you have any suggestions on how to make this as painless as possible - any tricks or methods you have tried and worked is much appreciated

I am also open to any other suggestions or recommendations you may have other than those listed above. I am also open to recommendations on cutting temperatures, angles etc.

Thank-you so much!

Philliesfan