ADSORPTIVE COMPLEX WAVE OF TIN(IV) WITH SOME THIAZINE DYES

Tin(IV) in a medium of sulfuric acid-oxalic acid with some thiazine dy es, e.g. new Methylene Blue (NMB) or Toluidine Blue (TB), at -0.60 V ( vs. SCE) produced a highly sensitive adsorptive complex wave. The sens itivity was increased to about 16-times higher than that without those dyes in the above-mentioned medium. The detection limit was 0.8 ng/ml (6.7X10(-9) mol/l) Sn(IV). The existing form and the apparent stabili ty constant (k) of these complexes, the reversibility of the electrode process, the character of adsorption and the mechanism of the electro de reaction were investigated, and a series of constants and parameter s were calculated. The proposed method was applied to determine trace tin in drinking-water samples and reagents with satisfactory results.