“…It has several advantages over other techniques, including stability and reusability of the solid phase, reach of high preconcenrtation factors, easiness of separation and enrichment under dynamic conditions, no need for organic solvents which may be toxic and minimal costs due to low consumption of reagents. Accordingly, several selective solid-phase extractors have been prepared by either physical loading or chemical binding of selected chelating reagents to different solid supports such as silica gel [14][15][16][17][18][19][20][21], activated carbon [22,23], cellulosic derivatives [24], polyurethane foam [25] and chelating ion exchange resins [26][27][28][29].…”