_1574513323 1574513323 Hamid Shirkhanloo sahar.zi67@gmail.com Hamid Shirkhanloo Analytical Methods in Environmental Chemistry Journal AMECJournal 2645-5382 2645-5552 09 25 2019 2 03 10.24200/amecj.v2.i03 http://journal.amecj.com/index.php/AMECJ-01/issue/view/9 *Ahmad Ghozatlu        In this study, the surface modification of graphene (SMG) was developed for efficient speciation and determination of chromium in water and wastewater samples. By procedure, the chromium ions were extracted from water/wastewater samples based on sulfonated and amine graphene (S-NG, N-NG) by suspension solid-phase microextraction procedure (SMSPE). Hydrophobic ionic liquid ([HMIM] [PF6]) was used for separation graphene from 10 mL of water. After shaking and centrifuging, the phase of Cr→ S-NG, Cr→N-NG was back-extracted by 0.2 mL of HNO3 (0.4 mol L-1) and finally chromium concentration determined with ET-AAS. The results showed the sulfonated and amine graphene can successfully extract Cr(III) and  Cr(VI) from water and wastewater samples at pH=3.5-5.5 and pH<3, respectively. Also, the most Cr(VI) extracted by N-graphene at pH=2(NH3+→Cr2O7─). Under the optimal conditions, the linear range, LOD, and preconcentration factor were obtained 0.02–2.4 µg L−1, 5.0 ng L−1 and 20.2, respectively for Cr(III, VI) (%RSD<5%).  09 26 2019 51 66 http://creativecommons.org/licenses/by/4.0 10.24200/amecj.v2.i03.67 http://journal.amecj.com/index.php/AMECJ-01/article/view/67 http://journal.amecj.com/index.php/AMECJ-01/article/download/67/121 http://journal.amecj.com/index.php/AMECJ-01/article/download/67/121 http://journal.amecj.com/index.php/AMECJ-01/article/download/67/131