Solid phase selective separation and green preconcentration of Cu, Zn, Pb and Cd in drinking water by using novel functionalized resin

A new solid - phase extraction sorbent was developed based on stepwise anchoring of two ligand molecules for the determination of copper, zinc, lead and cadmium in drinking water by flame AAS. Amberlite XAD-2 functionalized with 4'-(2-hydroxyphenylazo)-3'-methyl-1'-phenyl-2'-pyrazolin-5'-one (HPAPyr) was utilized for preconcentration/separation of these elements. The sorbent was prepared by two successive azo coupling reactions. First, 2-aminophenol was anchored to the amino groups in the resin resulted from nitration followed by reduction. Then, the resulted 2-aminophenol functionalized resin was further diazotized and coupled to the pyrazolone compound and the final product HPAPyr-XAD-2 was characterized by IR and elemental analysis. The optimum pH range for sorption, shaking time, exchange capacity, sample flow rate, preconcentration factor and interference from co-existing ions were investigated. All metal ions were quantitatively desorbed from the resin by 4.5 mol L-1 nitric acid solution. The sorbent provides limit of detection within the range 0.9-3.3 A mu g L-1 and concentration factor up to 250. The procedure was validated by analysis of certified material NIST-SRM 1577b. Application to drinking water showed satisfactory results with relative standard deviation RSD a parts per thousand currency sign 8.5%.