A new chelating resin is prepared by coupling Amberlite XAD-2 with salicylic acid (SAL) through an azo spacer. Then the polymer support was coupled with iminodiacetic acid (IDA). The resulting sorbent has been characterized by FT-IR, elemental analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) and studied for the preconcentration and determination of trace Pb (II) ion from human biological fluid and environmental water samples. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 67 mg g(-1). The chelating sorbent can be reused for 20 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 95% was obtained for the metal ion with 0.5M nitric acid as eluting agent. The profile of lead uptake on this sorbent reflects good accessibility of the chelating sites in the Amberlite XAD-2-SAL/IDA. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Pb (II) on modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich-Peterson models. Based on equilibrium adsorption data the Langmuir, Freundlich, and Temkin constants were determined 0.428, 20.99, and 7 x 10(-12) at pH 5 and 20 degrees C. The method was successfully applied for determination of lead ions in human plasma and sea water sample. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 1127-1136, 2011