Analysis of dithiocarbamate–thiuram disulfide mixtures

Abstract

The method presented for the determination of zinc, lead dialkyldithiocarbamates in the presence of tetraalkylthiuram disulfides is based on thiomercurimetric titration. Zinc, lead dialkyldithiocarbamates are determined by titration with p-dimethylaminophenylmercury(II) acetate with Michler's thioketone as indicator. Tetraalkylthiuram disulfides are reduced by using tributylphosphine and titrating as for metal dialkyldithiocarbamates. The method is simple, rapid, reproducible and accurate and samples do not require separation or other preliminary stages prior to their analysis. The method is suitable for the determination of metal dithiocarbamates and thiuram disulfides in fresh and used lubricants, and in additive concentrates and also may be adapted for the determination of dithiocarbamates in fungicides, rubber and plastics formulations.