Preconcentration of phosphate and arsenate at sub-ng ml−1 level with a chelating polymer-gel loaded with zirconium(IV) Original Research Article

In an acidic medium, a chelating polymer-gel loaded with zirconium(IV) rapidly adsorbed phosphate and arsenate, which were reversibly desorbed in an alkaline medium. By using a mini-column packed with this polymer complex, phosphate and arsenate at a sub-ng ml−1 level were quantitatively recovered in a flow system. Common cations and anions did not interfere with the adsorption; even fluoride did not interfere unless the total amount of fluoride, phosphate, and arsenate ions exceeded the active Zr sites. In combination with a molybdenum blue method for detection, the calibration based on their chemical amounts was achieved and the limits of detection defined by the signal-to-noise ratio=3 were 20 ng for P and 45 ng for As. Phosphate in environmental water was successfully determined. This preconcentration method may be combined with any detection system.