An efficient graphene/graphite paste sensor chemically modified by diphenylcarbazone for the detection of Al(III) ions in real water samples

•Efficient C past sensor is prepared modified with DPC and Gr for Al(III) detection.•Ip exhibits linearity over a wide analyte range from10 mM to 0.1 µM with LOD 31 nM.•Scan rate effect proves that Al(III)-DPC complex oxidation is under diffusion–controlled.•FT–IR, SEM and EDX characterization techniques were used to confirm the results.•The sensor is highly sensitive for Al(III) in spiked water with RSD less than 1%. These days development of efficient, selective and fast sensors for micro-determination of Al(III) in different samples is a highly demanding area of research. This is because aluminum intake is reported to have serious negative impact on human health. In this paper, a new electrochemical Al(III) sensor is developed based on a chemically modified carbon paste electrode with graphene nanosheets and diphenylcarbazone (DPC) ionophore. This sensor is chosen based on its highest sensing efficiency among the five fabricated carbon paste electrodes with varying compositions. Out of these five, two electrodes contain graphene with their two counterparts without graphene and the fifth one has the graphite paste only. Cyclic voltammetry and electrochemical impedance spectroscopy measurements are used for Al(III) detection in Britton–Robinson (B–R) buffer solution. Voltammetry results reveal good linear relationship between anodic redox peak current and Al(III) concentration over a wide range from 10 mM down to 0.1 µM with a very low limit of detection (LOD) 31 nM for the best sensor (electrode I) modified with graphene and DPC ionophore. This modified electrode is proved to be highly sensitive and selective towards Al(III) ion detection and is successfully used for determination of Al contaminant in spiked tap water and aqueous pharmaceutical preparation, as well as in drainage wastewater sample. The microstructure properties of this sensor relative to its counterpart having no graphene in its paste (electrode II) are also scrutinized with SEM, EDX analysis and FT–IR spectroscopy. [Display omitted]