Multi-element analysis of phytoplankton by tube-excited energy-dispersive X-ray fluorescence

The application is described of tube-excited energy-dispersive X-ray fluorescence analysis for the routine determination of some 20 elements in plankton algae filtered from brackish water. The samples were taken from an estuary in the Gulf of Finland and an archipelago outside the estuary. Both molybdenum and titanium /potassium secondary target radiation were used. Detection limits ranged from 0.3 ug per litre for bromine to 12 ug per litre for aluminium. Most of the environmentally important heavy metals were determined in all samples and a considerable degree of interrelation was found between several of them. A rapid multi-element method is described which is not considered to be sensitive enough for seawater analysis. Copper could not be determined since it was present in the blank filters at high and variable concentrations .