* Corresponding author: Moghimi, Ali  E-mail: alimoghimi@iauvaramin.ac.ir; kamran9537@yahoo.com  Tel number: +98 2136725011-14 © 2020 by SPC (Sami Publishing Company) Advanced Journal of Chemistry-Section A Theoretical, Engineering and Applied Chemistry Journal homepage: www.ajchem-a.com Original Research Article Preconcentration and Separation of Ultra-Trace Cu (II) with Disks of Octadecyl Silica Membrane Modified Nano-Fe3O4- Encapsulated-Dioctyl Phthalate and Linked-Diethylenetriamine Ali Moghimi *, Milad Abniki Department of Chemistry, Varamin-Pishva Branch, Islamic Azad University, Varamin ,Iran A R T I C L E I N F O A B S T R A C T Article history Submitted: 02 December 2020 Revised: 16 January 2021 Accepted: 01 February 2021 Available online: 01 February 2021 Manuscript ID: AJCA-2012-1230 DOI: 10.22034/AJCA.2021.260252.1230 In this study, an efficient method was performed to extract and measure the Cu(II) metal ions using the modified disks of octadecyl silica membrane by nano-Fe3O4-encapsulated-dioctyl phthalate and linked-diethylenetriamine (magnetic nano- Fe3O4 -DOP- DTA). This method involves forming a complex on the ENVI-18 DISK TM surfaces, followed by maintained species removed from the surface with the least amount of organic solvent. The act of elution in this technique is very impressive. The important factors are including the pH, stripping solvent, ligand values, rate of sample flow, and the effect of interfering ions were evaluated. The preconcentration factor was 500 in the optimum analysis situations of whole parameters. Analysis parameters contain the limit of detection and the most capacity of copper (II) ions sorption was achieved 6 μg/L and 385 ± 5 µg, respectively. Finally, the Cu 2+ ions were extracted in various aqueous solutions by this technique. K E Y W O R D S Cu 2+ Separation Octadecyl silica membrane Fe3O4-encapsulated Magnetic nano-Fe3O4-DOP-DTA Advanced Journal of Chemistry-Section A, 2021, 4(2), 78-86 G R A P H I C A L A B S T R A C T