Optimization of Solid-phase Extraction by Experimental Design Methodology for Determination of Lead Ions Using Graphene Modified Nano-sheets as a Novel Sorbent

A novel sorbent was synthesized by modification of graphene nano-sheets by pyridine group and characterized by transmission electron microscopy (TEM), thermal analysis (TG/DTA), elemental analysis (CHN) and infrared spectroscopy (IR). The application of this sorbent in determination of lead ions in environmental samples was investigated. Some parameters such as pH and time on adsorption process were optimized and introduced . The other parameters including eluent concentration, eluent volume and elution time which are important factors in desorption process were optimized by using a three-level three variables Box-Behnken experimental design. The limit of detection (LOD), the relative standard deviation and the recovery of the method were 3.5 ng mL-1, 2.2% and 98%, respectively. Finally the method was validated using several standard reference materials.