Microwave Exfoliated Graphene Oxide for Sorption Concentration of Gold and Silver

Abstract

A method has been reported for determining of Au and Ag in waters using preliminary sorption concentration of these analytes by microwave exfoliated graphene oxide (GO) and quantitative analysis by two-jet arc plasma atomic emission spectrometry (TJP-AES) and graphite furnace atomic absorption spectrometry (GFAAS). The parameters of sorption of analytes such as duration of sorption and pH were optimized for the preliminary concentration of Au and Ag on various carbon sorbents for subsequent TJP-AES and GFAAS analysis. The sorption properties of carbon nanotubes (CNTs), multilayer graphene (MLG) and GO such as sorption capacity and surface area were compared. The content of analytes in sorption materials was defined. The results demonstrated that GO provides the best sorption properties and the use of exfoliated GO for preconcentration decreaces the blank signal from nonselective absorption by 10 to 120 times. The limits of detection (LODs) for Au and Ag are 4·10−1 µg L−1 and 8·10−2 µg L−1 by GFAAS and 5 µg L−1 and 2·10−1 µg L−1 by TJP-AES.