Fe3O4 functionalized guanidine , a new adsorbent for determination of Pb, Cd, Zn and Cu by flame atomic absorption spectrometry was synthesized and characterized with different techniques. In this work, the effect of various parameters such as the pH, the type and volume of eluent, sample volume and interfering ions were optimized. After optimizing the experimental conditions, a linear calibration graph was obtained for determination of PbII, CuII, ZnII and CdII. The linear ranges were found to be 14-550 g L-1, 3 – 90 g L-1, 19 – 200 g L-1 and 40-600 g L-1 for Copper, Cadmium, Zinc, and Lead, respectively. The limits of detection were 4.78, 1.08, 7.6, and 11.8 g L-1 for Copper, Cadmium, Zinc, and Lead, respectively. The relative standard deviation for ten replicate determinations of PbII, CuII, ZnII and CdII were 3, 2.1, 2.9 and 1.2 respectively. The maximum capacity of the adsorbent was found to be 15.2 (±1.7) mg, 19.70 (±0.7) mg, 12.20 (±0.9) mg and 13.60 (±0.8) mg of PbII, CuII, ZnII and CdII per g functionalized magnetic nanoparticle, respectively. Applicability of the method was evaluated by analyzing trace amounts of Copper, Cadmium, Zinc, and Lead in different water samples.
