A disposable screen printed graphene-carbon paste electrode and its application in electrochemical sensing

In this work, an innovative, low cost and effective screen printed graphene-carbon paste electrode (SPGE) for advanced electrochemical sensing is reported. The SPGE is prepared by mixing electrolytically exfoliated graphene powder with carbon paste and is then screen printed on polyvinyl chloride substrate. The electrochemical device comprises three electrodes including SPGEs as the working and counter electrodes and silver/silver chloride paste as the reference electrode. Material characterization by electron microscopy and Raman spectroscopy confirms that the size of the multilayer graphene is in the range of 250-400 nm and that the carbon paste matrix is composed of 20-30 nm carbon nanoparticles. The electrochemical performances of the SPGE towards three of the most common electroactive analytes including hydrogen peroxide (H2O2), nicotinamide adenine dinucleotide (NAD(+)/NADH) and ferri/ ferro cyanide (Fe(CN) 6 (3-) (/4-)redox couples are characterized. It is found that graphene inclusion considerably enhances electrochemical responses towards the analytes, with 10% being an optimum graphene concentration. The oxidation signals for H2O2, NADH and K4Fe(CN)(6) of the SPGE with the optimal graphene concentration are found to be similar to 2.0, similar to 1.8 and similar to 1.7 times higher than those of a screen printed carbon paste electrode, respectively. In addition, excellent analytical features with relatively wide dynamic ranges, high sensitivities, low detection limits and high reproducibility are achieved. Therefore, the SPGE is a promising candidate for low-cost and advanced electrochemical sensing applications.