Photometric determination of sulfide. • DIN method: N,N-Dimethyl-1,4-phenylene diamine reacts with hydrogen sulphide to form a compound which changes to leucomethylene blue. This compound is oxidised to methylene blue using iron(III) ions (Reaction basis according to DIN 38405-D26/27). • Sulphide is measured in an acidic medium; vigorous mixing can cause evaporation of gaseous hydrogen sulphide which escapes analysis. • Type: tube test 0-73 • Range: 0.05 - 3.00 mg/l S2- • Sufficient for: 20 determinations • Sea water suitability: yes, after dilution (1+3)