ORIGINAL PAPER A magnetized graphene oxide modified with 2-mercaptobenzothiazole as a selective nanosorbent for magnetic solid phase extraction of gold(III), palladium(II) and silver(I) Mahmoud Reza Neyestani 1 & Farzaneh Shemirani 2 & Shahla Mozaffari 1 & Mahrouz Alvand 2 Received: 13 December 2016 /Accepted: 25 April 2017 # Springer-Verlag Wien 2017 Abstract This article describes a useful sorbent for separation and preconcentration of trace amounts of gold(III), palladium(II) and silver(I) ions. Graphene oxide (GO) nanoparticles were syn- thesized by a modified Hummers method and magnetized by MnFe 2 O 4 nanoparticles to give a sorbent referred to as mag-GO. Addition of sodium dodecyl sulfate creates admicelles on the surface of the mag-GO. Then the metal chelating agent 2- mercaptobenzothiazole (MBT) was immobilized on mag-GO to give a mag-GO-MBT type material. This adsorbent was ap- plied to the preconcentration of gold(III), palladium(II) and silver(I) ions. Following ion desorbed with a solution of thio- urea, the ions were quantified by flow injection coupled to ICP- OES. Effect of sample pH value, type and volume of eluent, amount of adsorbent, sample volume, time of adsorption and desorption were optimized. Under optimized condition, the cal- ibration plots are linear in the 2.5 to 25,000 μg.L -1 concentration range. The limits of detection range from 0.045 to 0.076 μg.L -1 , and enhancement factors are 160, 160 and 140 for gold, palla- dium and silver ions, respectively. Precisions, expressed as rel- ative standard deviation for 100 μg.L -1 of each ion are <3.1%. The nanosorbent applied to selective adsorption, extraction and preconcentration of Au(III), Pd(II), and Ag(I) from water, ore and automobile catalyst samples. Keywords Modified magnetic GO nanoparticles . Preconcentration . MnFe 2 O 4 . Precious metals . Thiourea . ICP-OES . Automotive catalyst Introduction Precious metals are found in process and wastewater streams of various industries including mining, ore and metal processing, semiconductor and electronic manufacturing and e-waste recycling [1–3]. Gold is ex- tensively used in various areas such as the petrochemi- cal industry, medicine, electronics and nuclear power industries [4]. The release of palladium from Vehicle Exhaust Catalysts (VECs) represents a source of highly dispersed environmental contamination, and this metal have been identified in dusts, soils and waters [5]. Silver and its compounds have an essential role in elec- tronic and electrical applications, photographic film pro- duction, dental and pharmaceutical preparations, and manufacturing of fungicides [6]. Based on the low con- centration of these metal ions (Au, Pd and Ag) in the environment and biological samples and their matrix effects, a very sensitive method is necessary for accu- rate and precise determinations. Although atomic ab- sorption spectrometry (AAS) [ 7 ] and inductively coupled plasma-atomic emission spectrometry (ICP- AES) [8] are among the most widely used methods for trace metal determination, the interference caused by the sample matrix still exists and is perhaps it is the most serious problem, so making a pre- Electronic supplementary material The online version of this article (doi:10.1007/s00604-017-2299-8) contains supplementary material, which is available to authorized users. * Mahmoud Reza Neyestani neyestani2533@gmail.com 1 Department of Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran 2 Department of Analytical Chemistry, University College of Science, University of Tehran, P.O. Box 14155-6455, Tehran, Iran Microchim Acta DOI 10.1007/s00604-017-2299-8