[en] Full text: In this work, water-soluble superparamagnetic iron oxide nanoparticles (SPION) had been prepared by polyol method (according to Cai et al.) in order to obtain uniform and highly crystalline stable superparamagnetic nanoparticles, using different ferric precursor Fe(acac)₃ and Fe(NO₃ )₃ .9H₂O and different initial ferric concentration (IC) leading to formation of monodisperse iron oxide nanoparticles. Size and morphology of the nanoparticles were determined using transmission electron microscope (TEM). Crystal structure was identified by X-ray powder diffraction (XRD). Magnetic properties of iron oxide nanoparticles at different temperatures were studied using a VSM and a SQUID magnetometer. Particles synthetized from Fe(acac)₃ were named as MA and particles synthetized from Fe(NO₃ ).9H₂O as MN, respectively. The MA nanoparticles exhibited a spherical morphology meanwhile the MN ones depicted a more irregular symmetry . For MA samples, the IC value appeared to have no influence on average diameter of the nanoparticles in contrast with MN ones which the IC affected directly the average diameter of nanoparticles, increasing in sizes with the higher value of IC. The nanoparticles are well-crystalline and the position and relative intensity of the diffraction peaks of the samples match well with the standard XRD data for bulk magnetite. The magnetization curve at ambient temperature of all samples exhibited a superparamagnetic behavior without coercivity and remanence. The IC affected the saturation magnetization of the SPION. Reference: [1]. Cai W.et al., J. Colloid Interface Sci. 305 (2007) 366-370. (author)