Development and characterization of a novel electrochemiluminescent reaction involving cadmiumElectronic Supplementary Information available. See http://www.rsc.org/suppdata/an/b0/b004527f/

Abstract

Electrochemiluminescent reactions involving aqueous metal ions can offer an alternative method for quantitation of dissolved metals. In this case, a flow injection system using 1,10-phenanthroline as an ECL reagent, in conjunction with Cd²⁺ ions provides sufficient emission for cadmium detection down to 1 ppb. The high throughput of flow injection analysis combined with the relatively simple ECL instrumentation gives a potentially fast and inexpensive method for routine aqueous cadmium determinations. Parameters such as applied potential, buffer composition, flow rate, cell shape and volume, and electrode material were investigated. A survey of possible interferent ions proved the reaction to be fairly selective for the Cd²⁺ ion. During these studies, a competing ECL reaction involving Zn²⁺ was discovered. The ECL spectrum was recorded and a mechanism for ECL emission is postulated.