Cadmium, Lead, and Copper Stability

Donavon had a question regarding the stability of a blend made up of 1000 ppm Cd, Pb, and Cu. He wondered if this solution would be stable for the same amount of time as the individual standards. Donavon also noted that the standard would be used in Anodic Stripping Voltammetry.

	RE: Cadmium, Lead, and Copper Stability Dear Donavon,      A Cd, Pb, and Cu mixture in a dilute nitric acid matrix packaged in LDPE bottles cleaned with nitric acid would be ideal. Your blend would be stable indefinitely based upon transpiration studies conducted on single and multi-component systems. There are no inter-metallic compounds formed, nor is there photo-sensitivity under these conditions. If you have experienced instability, look for the presence of impurities such as trace amounts of sulfate, chloride, or organics. These impurities can be found in the water and the apparati used to prepare the standards and storage containers.      If you have any further questions please contact me and best of luck with your anodic stripping experiments.     Paul R. Gaines, Ph.D. Serving you in chemistry