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We are introducing graphene oxide modified with amine groups as a new solid phase for extraction of heavy metal ions including cadmium(II), copper(II), nickel(II), zinc(II), and lead(II). Effects of pH value, flow rates, type, concentration, and volume of the eluent, breakthrough volume, and the effect of potentially interfering ions were studied. Under optimized conditions, the extraction efficiency is >97 %, the limit of detections are 0.03, 0.05, 0.2, 0.1, and 1 μg L(-1) for the ions of cadmium, copper, nickel, zinc, and lead, respectively, and the adsorption capacities for these ions are 178, 142, 110, 125, and 210 mg g(-1). The amino-functionalized graphene oxide was characterized by thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectrometry. The proposed method was successfully applied in the analysis of environmental water and food samples. Good spiked recoveries over the range of 95.8-100.0 % were obtained. This work not only proposes a useful method for sample preconcentration but also reveals the great potential of modified graphene as an excellent sorbent material in analytical processes.

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An efficient procedure for the synthesis of 2,4,6-triarylpyridines (Kröhnke pyridines) by the one-pot multicomponent condensation of aldehydes (1 equiv) with acetophenones (2 equiv) and ammonium acetate (1.2 equiv) in the presence of catalytic amounts of oxozirconium(IV) chloride (ZrOCl 2 ) under solvent-free conditions is described. In this work, four products have been reported for the first time. Easy work-up, simple methodology, clean reaction and reusability of the catalyst are some advantages of this work.