Vol.:(0123456789) 1 3 Journal of Food Measurement and Characterization https://doi.org/10.1007/s11694-019-00057-z ORIGINAL PAPER Construction of novel nonenzymatic Xanthine biosensor based on reduced graphene oxide/polypyrrole/CdO nanocomposite for fish meat freshness detection Kh. Ghanbari 1  · F. Nejabati 1 Received: 27 October 2018 / Accepted: 28 January 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract A novel nonenzymatic voltammetric Xanthine biosensor was constructed based on a three-dimensional porous nanocom- posite of reduced graphene oxide/polypyrrole/CdO nanocomposite modified glassy carbon electrode (GCE/rGO/PPy/CdO) for measuring of Xanthine. The structure and morphology of rGO/PPy/CdO nanocomposites were characterized by field emission scanning microscopy, Raman spectroscopy, X-ray diffraction, UV–vis spectroscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. The GCE/rGO/PPy/CdO based biosensor exhibited excellent electrocatalytic activity and high stability for Xanthine oxidation. Under optimized conditions, the linearity between the current response and the Xanthine concentration was obtained in the range of 1–800 µM with a detection limit of 0.11 μM (S/N = 3). The biosensor was used to determine the Xanthine in fish meat with satisfactory results. Keywords Nonenzymatic biosensor · Xanthine · Reduced graphene oxide · CdO nanostructures · Polypyrrole Introduction Xanthine (3,7-dihydro-purine-2,6-dione) is produced by the destruction of guanine and hypoxanthine and is present in most tissues and body fluids, such as urine and blood. Xanthine can be used not only as an indicator of inborn metabolic disorders and diseases, like Xanthinuria, hyper- uricemia, gout, and renal failure, but it is also regarded as a major criterion when monitoring the freshness of meat in the food industry, for instance fish meat [1]. According to the literature, several analytical methods can be applied for Xanthine determination such as electrochemical biosensors based on immobilized xanthine oxidase (XOD) in addition to high performance liquid chromatography (HPLC) [2], mass spectrometry [3], and capillary electrophoresis [4]. All these referenced methods for determining Xanthine are often complex and very costly and in some cases, sensitivity, selectivity, stability, and repeatability are not good. However, in biosensors based on immobilized XOD enzyme, owing to the nature of enzymes, this XOD immo- bilized sensor suffered from the influence of temperature, humidity, pH, and toxic chemicals etc [1]. In addition, the immobilization procedure of XOD is complicated. There- fore, nonenzymatic Xanthine biosensor was suggested as an alternative to XOD based sensors. In this work, we modified the surface of the bare electrode without applying any enzyme. We used a variety of com- pounds such as carbon nanomaterials, conductive polymers, and metal oxide nanoparticles to modify the surface. To improve the performance of the electrode in order to create a complete substrate for determining biomolecules and reduce the charge transfer resistance at the sensor sur- face, electrode surface modification is an important [5]. Conducting polymers (CPs) and nanomaterials are good choices for modification of electrodes due to good conduc- tivity and high surface area. Among the CPs, polypyrrole (PPy) was applied often in biosensors, since it is biocom- patible with high conductivity and can be easily deposited at a surface of electrode [6]. As well as, the presence of the amine group (–NH–) on the pyrrole ring may result in Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11694-019-00057-z) contains supplementary material, which is available to authorized users. * Kh. Ghanbari kh_ghanb@yahoo.com; kh.ghanbari@alzahra.ac.ir 1 Department of Chemistry, Faculty of Physics and Chemistry, School of Science, Alzahra University, 1993891167 Vanak, Tehran, Iran