Detection of heavy metals in water by fluorescence spectroscopy: On the way to a suitable sensor system

In order to develop a fiber optical heavy metal ion detection system, the applicability of selected complexing agents with fluorescent properties has been studied. Beginning with the application of known chelators, like BTC-5N, Newport Green™, neocuproine, and chromotropic acid, a sensor configuration has been found, which allows the detection of Cd²⁺, Ni²⁺, and Cu²⁺ well below the chemical parameter threshold values of the new Water Quality Directive 98/83/EU. The sensor itself uses a membrane separation of the chelator flow from the sample volume. The diffusion across the membrane limits the response time to about 15 to 20 min. Applications are seen in monitoring networks.