Solid phase extraction (SPE) coupled to electrochemical detection on screen-printed carbon electrode (SPCE) has been developed for the quantification of mercury ions in aqueous samples. Mercury ions were extracted using Iron(II, III) oxide magnetic nanoparticles modified with poly(1,8-diaminonaphthalene) [Fe3O4/PDAN] as a sorbent. The adsorbed mercury ions were removed from the polymeric matrix using 1 mL of HCl (0.1 mol L-1) as the eluent. Then, in order to determine the concentration of mercury ion, this solution was analyzed by means of screen printed electrochemical strips. Differential pulse voltammetry (DPV) anodic charge at 0.05 V was selected as the identifying signal and subsequently the influence of experimental parameters affecting the adsorption and desorption steps were investigated and optimized using one-variable-at-a-time methodology as follows: pH of the sample solution, 7.0; amount of the sorbent, 10 mg; adsorption time, 10 min; type of the eluent, HCl; concentration of the eluent, 0.1 mol L-1; volume of the eluent, 1 mL and desorption time, 5 min. Finally, a calibration curve was plotted by the variation of DPV anodic charge as a function of mercury concentration which was linear within the range of 0.1-30.0 ng mL(-1). The limit of detection and the limit of quantification were 0.03 (S/N = 3) and 0.1 ng mL(-1), respectively. (C) 2016 The Electrochemical Society. All rights reserved.