Dual-wavelength spectrophotometric determination of trace sulphide in domestic water through its ligand-exchange reaction with silver-Cadion 2B-triton X-100.

Trace amounts of S(2-) can be determined by means of the exchange reaction with the Ag(+)-Cadion 2B complex in presence of Triton X-100 and Na(2)B(4)O(7) solution, by dual-wavelength spectrophotometry. Beer's law is obeyed for the sulphide range 0-2.0 microg/25 ml . The apparent molar absorptivity is 2.65 x 10(5) l.mole(-1).cm(-1). The effect of diverse ions in the presence of EDTA has been studied. The interferences produced by some anions in water samples can be eliminated by precipitation with zinc acetate.