Do you mean a frigidair freezer or refridgerator? For a freezer, long term storage is okay; the organotins should be stable when biological activity has ceased, water is frozen and it is dark. At above freezing, you have to consider microbial degradation. The rate constant for TBT in sediments (no temperature specified) given in Rahnke (2002) is given as 0.24 yr-1; converting that to a half-life = ln (2)/0.24 = 3 years. Though this is uncertain, it would imply that storage for weeks or even a few months may not effect sediment concentrations in a refridgerator (but this is risky). Degradation rates in water and porewater are much faster (0.061 day-1, or a half life of 11 days). Therefore if you have to store a water sample above freezing for more than a day or two, add a biocide like NaN3 at 1g/L. For biota, freezing is the only option. Good luck!
Ref, Ranke, J. (2002) Persistence of Antifouling Agents in the Marine Biosphere. Environmental Science & Technology 36(7), 1539-1545.
it depends, the extraction volume and the expecting concentration of butyltin in your extract. mainly, we prefer the direct analysis after extraction. However, no evidence that the long time has effect on the concentration of butyltin in the extract, except the risk of adsorption of the analytes on the surface of the glass. Therefore if you have to store your extract, i believe that two or three weeks at - 4C in refrigerator will be OK, but not more.
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