Photometric determination of lead. • Photometric determination with 4-(2-pyridylazo)-resorcinol (PAR). • In the presence of cyanide lead(II) ions react with 4-[pyridyl-(2)-azo]-resorcinol (PAR) to form a red dye. If interfering heavy metals are present, only the red lead complex is destroyed and the colour decrease is measured photometrically. • Type: tube test 0-09 • Range: 0.10 - 5.00 mg/l Pb2+ • Sufficient for: 20 determinations • Sea water suitability: no