Butyltin chlorides determination

Hodge et al. [92] have described an atomic absorption spectroscopic method for the determination of butyltin chlorides and inorganic tin in natural waters, coastal sediments, and macro algae in amounts down to 0.4 ng. 

An estimate of the accuracy of both analytical methods was performed on bis(tri-n-butyltin) oxide and tri-n-butyltin chloride solutions (8.9-35.6 ig/l) prepared in filtered (0.45 im) near-shore seawater free of detectable organ-otins. Average mean recoveries of 92.8% by both methods were determined for tributyltin standard solutions. Low ng/1 levels of mono-, di-, and tributyltin were found in samples taken from San Diego Bay. 

The determination of the Concentrations in pyridine [N] which cause the coalescence of the signals of the diastereotopic groups of a 0.262 M solution methylneophyl-t-butyltin bromide (6) and of 0.332 M solution methylneophylphenyltin chloride (3) at 22 °C at respectively 60, 100 and 270 MHz shows12) that the k2 term is much smaller than the k3[N] term. From these results, it is clear that the inversion of the configuration of the metal atom of triorganotin halides is second-order in the nucleophile pyridine. An analogous rate equation has been found for the racemiza-tion of triorganosilicon halides 29), for which the activation entropy AS is about —50 e.u. Several mechanisms with increase of coordination number 30) can be proposed to account for this second order in the nucleophile 31) ... 

Unger et al. [217] determined butyltins in non saline water by gas chromatography with flame photometric detection and confirmation by mass spectrometry. The sample was extracted with tropalone in //-hexane and organotin compounds derivatised with n-hexyl magnesium bromide to form tetraalkyltins. The n-hexyl derivatives of methyltin and butyltin species were easily separated and quantified relative to an internal standard (triphenyltin chloride) which was not found to be present in environmental samples and did not interfere. 

Tri-n-butyltin bromide (TBT), triethyltin bromide (TET), and trimethyltin chloride (TMT) inhibited the cardiac SR Ca uptake (Figure 4.1.2) and Ca +-ATPase (Figure 4.1.3) in vitro in rat heart in a concentration-dependent manner. The order of potency for Ca +-ATPase as determined by IC50, is TBT (2 pM) > TET (63 pM) > TMT (280 pM). For Ca uptake, it followed the same order, i.e., TBT (0.35 pM) > TET (10 pM) > TMT (440 pM). In agreement with them vifro results, both cardiac SR Ca +-ATPase and Ca uptake were significantly inhibited in vivo in rats treated with these organotin compounds... 

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