Separation/Preconcentration and Speciation Analysis of Trace Amounts of Arsenate and Arsenite in Water Samples Using Modified Magnetite Nanoparticles and Molybdenum Blue Method - Mohammad Ali Karimi; Alireza Mohadesi; Abdolhamid Hatefi-Mehrjardi; Sayed Zia Mohammadi; Javad Yarahmadi; Azadeh Khayrkhah (Journal of Chemistry)