Photometric determination of copper. • Photometric determination with cuprizone (oxalic acid bis-cyclohexylidene hydrazide). • In weakly alkaline solution copper(II) ions react with cuprizone [oxalic acid bis(cyclohexylidene hydrazide)] to form a blue complex. • Type: standard test 1-53 • Range: 10 mm cuvette: 0.1 - 10.0 mg/l Cu2+ 50 mm cuvette: 0.01 - 2.00 mg/l Cu2+ • Sufficient for: 250 determinations • Sea water suitability: yes