US EPA

2299796 

Technical Report 

Antifouling Paints Based on Organotin Compounds. Part II: Spectrographic Determination of Microgram Amounts of bis-(tri-n-butyltin)oxide in Aqueous Solutions 

Chromy, L; Mlodzianowska, W; Uhacz, K; Warchol, R 

1970 

NIOSH/00130075 

53 

121-126 

A spectrographic method for determining microgram amounts of bis-(tri-n-butyltin)oxide (56359) (TBTO) was evaluated. Measurements were made using a medium resolution spectrograph with a range up to 3,000 angstroms. Standards were prepared for TBTO with ratios of 0.008 percent TBTO to 0.002 percent tin, and 0.016 to 0.004 percent, 0.032 to 0.008 percent, and 0.080 to 0.020 percent TBTO to tin, respectively. Samples of TBTO of unknown concentration were extracted with carbon-tetrachloride, then mixed with 0.5 gram carbon containing 0.5 percent of a copper internal standard. Samples were dried and excited, then measured. The accuracy of spectrometric and colorimetric methods was compared. The spectrographic method allowed determination of TBTO in carbon-tetrachloride solution at a concentration limit of about 5 parts per million (ppm). It was also easy to determine TBTO in aqueous solutions at concentrations of 1ppm, provided no other carbon-tetrachloride soluble organotin compounds were present. The authors conclude that the method is useful in following the leaching process of TBTO from antifouling paints. The electrographic determination method is more accurate than the colorimetric method for determining microgram amounts of organotin compounds.