The influence of sample preparation on the 119mSn Mössbauer spectrum of tributyltin chloride in ponderosa pine was investigated. Initial studies with sawdust and compressed discs concluded that the latter were clearly superior. Further studies showed that compressed discs prepared from 0.4 g of treated wood and 0.1 g of cellulose were robust and gave excellent Mössbauer spectra. The possibility of improving the Mössbauer resonance by increasing the solution concentration was evaluated, and found to be beneficial, with no change in the fixation process being evident at least up to 6.9% solution strength. Wooden cores were assessed as alternative test material since they are less prone to disintegration. The Mössbauer spectrum of tributyltin chloride in wood was obtained and analyzed with the aid of point charge calculations. It was concluded that when impregnated into wood, tributyltin chloride either remains polymeric with bridging chlorides or adopts a mer-trigonal bipyramidal geometry with hydroxyl donor bonding from the cellulose. Investigation of tributyltin-, dibutyltin- and monobutyltin-chlorides following impregnation into wood suggested that, while the monobutyltin-derivative may be easily identified when present, it is doubtful whether the tributyltin- and dibutyltin- complexes will be distinguishable using simple Mössbauer spectroscopy. Modifications were therefore proposed for the technique which would allow the triorgano- and diorganotin species to be identified when present as mixtures in wood.

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