ISO International Standard

The specified method is applicable to sulfide determination in a mass concentration range from 0,04 mg/l to 1,5 mg/l. The following ions do not interfere in specified mass concentrations: cyanide, iodide, thiosulfate, thiocyanate, sulfite. The principle is filtration, conservation of the sulfide in the filtrate, stripping of the sulfides, formation of leukomethylene blue, measurement of the absorbance of this complex at a wavelength of 665 nm. Annex A describes standardization of sulfide stock solution.