Antifouling paint, determination

A combination of HPLC and amperometric detection was proposed for determination of tributylstannyl oxide in antifouling paint. The detector is of the static hanging Hg drop type in a flow cell, the solvent is CH2CI2/THF, containing tetrabutylammonium perchlorate as supporting electrolyte. The oxidation mechanism depicted in reactions 4... 

The amount of biocides needed in an antifouling paint will be determined by actual tests performed in real life. A rule of thumb says that the minimum level of protection with copper is a leaching rate of 10 pg/(cm2 day) (WHOI, 1952). The amount of cuprous oxide can be up to 40 wt % of an antifouling paint and it is normally assisted by booster biocides (5 to 10 wt %) to provide full protection against both animals and algae. The amount of biocides will be based on practical performance and, at the same time, be restricted to given legislation. 

Benzothiazoles from vulcanization of rubber tires are found so enriched in some situations that they are used as a marker for street run-off water. Thiocya-natomethylthiobenzothiazole used as a fungicide in wood protection and antifouling paints may degrade into benzothiazoles and methylthiobenzothiazole is used in vulcanization processes, so these materials find their way into rivers and ultimately estuaries. Bester et al. (1997) determined the presence of benzothiazole and methylthiobenzothiazole in estuarine and marine waters. Their concentrations range from 0.04 ngL to 1.37 ngL . Methylthiobenzothiazole and benzothiazole vary from 0.25 ng L to 2.7 ngL in the North Sea, while 55 ngL methylthiobenzothiazole was found in the Elbe River. 

This compound is released in the marine environment from the leaching of TBT-based antifouling paints used on boats and ships and its use has now been regulated in several countries. Other compounds are known to be very toxic to marine life, e.g. triphenyltin, and these compounds, along with their degradation products, are currently determined routinely by some laboratories to underpin controls of the levels of environmental contamination. These analyses are particularly requested in support of some EC directives [19]. 

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