Kinetic spectrophotometric determination of sulfide, using in-cuvette mixing and titration techniques with computerized data acquisition

In-cuvette mixing and titration techniques have been used for the kinetic d etermination of sulfide based on its inhibition effect on the oxidation of indigo carmine with hexacyanoferrate(III) in the presence of silver. The re action was monitored spectrophotometrically by measuring the decrease in ab sorbance of indigo carmine at 612 nm. Both initial rate and fixed-time meth ods were applied to the in-cuvette technique. Using in-cuvette mixing, sulf ide up to 1800 ng was determined and detection limit and relative standard deviation for the determination of 120 ng of sulfide were calculated as 23. 0 ng and 1.59%, respectively. On the basis of the titration technique, the upper limit of determination was 25 mu g of sulfide and detection limit and average relative standard deviation for the determination of 1 mu g of sul fide were 0.025 mu g and 4.95%, respectively. The effect of foreign ions;on the sulfide determination was studied. The proposed methods were applied t o the determination of sulfide in water.