%0 Journal Article
%T Synthesis and Characterization of Functionalized Magnetic Nanoparticles for the Detection of Pesticide
%A Shu Taira
%A Daisaku Kaneko
%A Kazuki Onuma
%A Akio Miyazato
%A Tomoyuki Hiroki
%A Yasuko Kawamura-Konishi
%A Yuko Ichiyanagi
%J International Journal of Inorganic Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/439751
%X We synthesized magnetic nanoparticles (MNPs) by mixing aqueous solutions of 3d transition metal chlorides ( ) and a sodium metasilicate nonahydrate ( ) in order to produce monodispersed MNPs in a single step. The particle size can be controlled by adjusting the annealing temperature. We characterized the MNPs by X-ray diffraction (XRD), superconducting quantum interference device (SQUID), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and zeta-potential measurement. Paramagnetic and superparamagnetic behaviors were found for the obtained samples depending on the particle size ( ˋnm). The synthesized MNPs could be modified with the amino-, phenyl-, and carboxy- groups on MNPs' surface by silanization procedure, respectively. The purpose of functionalizing the surface of the nanoscale magnetic particles was to realize subsequent capture and detection with desired other molecules by nanoparticle assisted laser ionization/desorption mass spectrometry. 1. Introduction Nanoscale magnetic particles have attracted much attention because they are able to be transported to targeted locations [1每4] by means of an external magnetic field as well as to be used for data storage [5] and magnetic resonance imaging [6, 7]. Synthesis methods of magnetic nanoparticles (MNPs) have been developed for composing various kinds of MNPs and controlling the sizes in the range of 1每100ˋnm [8每10]. Coprecipitation method is the most convenient way to synthesize MNPs from metal chloride solution (i.e., iron, manganese, nickel, etc.) by the addition of base solution. MNPs are precipitated under optimum temperature, pH, and ionic strength [11每13] due to solubility change. Nanometer-scale spheres show very interesting characteristic phenomena such as quantum size effect or magnetic quantum tunneling and have intrinsic instability over longer haul for the morphology. To stabilize MNP character, chemical coating on naked MNP surface was developed [14每16]. For example, MNP with 10每20ˋnm can be stabilized in 2-aminoethanethiol (0.5ˋM) [14]. Polymer or surfactant coating is also used to protect the MNP configuration and avoid aggregation [17每21]. These techniques can be applied to protection of MNP morphology although we should pay attention to synthesis conditions under the complicated method. We have developed a method for synthesizing MNPs by mixing aqueous solutions of 3d transition metal chlorides (MCL2﹞nH2O) and a sodium metasilicate nonahydrate (Na2SiO3﹞9H2O) to obtain monodispersed and bite-sized MNPs in a single step. The particle size depended on the
%U http://www.hindawi.com/journals/ijic/2012/439751/