A device, system and method for detecting and measuring concentrations of elements in fluids comprises: flowing a fluid through a central flow interelectrode gap of an ionic preconcentration cell separating an upper high specific surface area electrode from a lower high specific surface area electrode of the ionic preconcentration cell by a predetermined interelectrode gap width; and applying a voltage differential between the upper high surface area electrode and the lower high surface area electrode while the fluid is flowing through the central flow interelectrode gap. As such, this cell that utilizes its inherent capacitance for double layer formation to extract ultra-trace levels of ionic contaminants from fluids in order to enhance detection by x-ray fluorescence analysis.