Environmental concerns organotin compounds

Heat stabilisers for PVC act by HC1 scavenging and include organotins, mixed metal salt blends, and lead compounds. The latter account for nearly 64 % of volume (in 1994), followed by barium/cadmium and organotin compounds. Cadmium-based heat stabilisers are rapidly being replaced due to environmental concerns. Barium/zinc and calcium/zinc compounds show a high growth rate. It is expected that methyltin stabilisers will soon dominate the growing PVC pipe market. 

Elsewhere in The Chemistry of Functional Groups series appears a brief discussion on the stages in the lifetime of chemicals2. Organotin compounds are usually very toxic and they constitute a potential source of harmful pollution with both acute and longterm effects. Increasing concern with environmental and occupational issues has also contributed to the development of analytical methods. Table 1 lists organotin compounds that have found industrial application with references to occupational protection protocols where analytical methods for the particular compound can be found. 

Organotin catalysts have been tested as well with good results for the transesterification of oils. Unfortunately, these compounds are very soluble in fatty acid esters, complicating their separation and adding to environmental concerns. ... 

The main criterion for the detector is that it gives a response specifically for tin, rather than the compound. This is because of the detection limits required for environmental analysis, which are not attainable with non-specific detectors. The most popular detection methods for organotin analysis are FPD using a tin selective filter, MS, MIP-AES, and ICP-MS. Recently, HPLC-MS methods based on atmospheric ionization including electrospray, ion spray, or chemical ionization have been used to detect the organotin species. These methods have the advantage that molecular information concerning the analyte is available, rather than just atomic information. 

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