INSTRUMENTALLY SIMPLE FLOW DETECTOR FOR THE DETERMINATION OF TRACES OF ELECTROLUMINESCENT COMPOUNDS IN AQUEOUS-SOLUTIONS

A flow detector based on the observation of the cathodic electroluminescence at an oxide-covered aluminium electrode is described. The detector responds only to electroluminescent compounds in aqueous eluents, and additional selectivity can be achieved by making use of optical filters for wavelength discrimination. The optimum detection conditions were determined by using the cathodic electroluminescence induced by a polynuclear aromatic hydrocarbon in micellar solutions as the model electroluminescence. This instrumentally simple detector can be used to determine electroluminescent compounds in a wide concentration range with good precision. For instance, its detection limit, dynamic range and precision (i.e., relative standard deviation for 20 successive measurements of 1 × 10-7 M samples) for the determination of micelle-encapsulated 9,10-diphenylanthracene were found to be 1 × 10-8 M, four orders of magnitude and 7%, respectively. © 1990.