Photometric determination of chlorine. • Photometric determination of free and total chlorine with N,N-diethyl-1,4-phenylene diamine (DPD). • Free chlorine, total chlorine and ozone react with DPD (N,N-diethyl-1,4-phenylene diamine) to form a red-violet dye. By defined addition of iodide ions one can differentiate between the individual components. • Type: standard test 1-16 • Range: 10 mm cuvette: 0.1 - 10.0 mg/l Cl2 50 mm cuvette: 0.02 - 2.00 mg/l Cl2 • Sufficient for: 250 determinations • Sea water suitability: yes