Reagents
Analytical grade acetic acid, hexane and methanol
were purchased from Merck, Germany and used without
further purification. Butyltin trichloride, dibutyltin
dichloride, tributyltin chloride and sodium tetraethylborate
were from Strem Chemicals, France. Certified
reference material PACS-I was purchased from the
National Research Council, Division of Chemistry,
Ottawa, Canada. The values for the butyltin species (as
ng butyltin ion g-I) in this material are: TBT
3103 i 537 (certified), DBT 2276 + 353 (certified) and
MBT 414 i 252 (indicative value).