Typical chromatograms for a lake water and the effluent of a
WWTP are shown in Figure 4. The separation of the EDTA peak
is very good for both matrices. Chromatograms from river water
or groundwater look similar to that for the lake water, which is
shown in Figure 4b. The detection limit, based on a signal-tonoise
ratio of 3 and a preconcentration of 2, is 3 10-9 M. This
method has, therefore, the same detection limit as the HPLC
method of ref 8