Colorimetric Determination of Organotin Hydrides with Isatin or Ninhydrin

Two new colorimetric methods were developed for the quantitative determination of organotin hydrides. They are based on the reduction of the carbonyl groups of isatin or ninhydrin by organotin hydrides. In the first case colourless dioxindole is formed, and the lowering in the optical density of an isatin solution is taken as the basis for the determination. In the second case the coloured salt of 2-hydroxyindanedione is formed. The reactions are sensitive and it is possible to determine concentrations of organotin hydride to about 10−4 mole/1.