Determination of cadmium in marine waters: on-line preconcentration and flow-through fluorescence detection

This paper reports the development of a new molecular fluorescence spectros copy method for the determination of cadmium in marine waters. An anthrylhe xaazamacrocycle was used as a fluorogenic reagent at pH 13. Ionic extractio n chromatography on Dowex resin was necessary to separate cadmium from the matrix and especially from lead, mercury and organic matters present in sea water and interfering with the fluorescence measurements. The coupling of o n-line preconcentration by Dowex resin and fluorescence flow-through detect ion at pH 13 led to a detection limit of 35 pM for a preconcentration time of 5 min (2.1 ml min(-1)). The accuracy of the method was verified on certi fied seawater samples SLEW-2 and NASS-5. Water samples collected in the Sch eldt estuary near Antwerp (Belgium) during an ebb tide were analysed for di ssolved cadmium. (C) 2001 Elsevier Science B.V. All rights reserved.