Sensors and Actuators B 233 (2016) 298–306 Contents lists available at ScienceDirect Sensors and Actuators B: Chemical jo u r nal homep age: www.elsevier.com/locate/snb Preparation and characterization of gold nanoparticles decorated on graphene oxide@polydopamine composite: Application for sensitive and low potential detection of catechol Selvakumar Palanisamy a , Kokulnathan Thangavelu a , Shen-Ming Chen a,∗ , Balamurugan Thirumalraj a , Xiao-Heng Liu b,∗ a Electroanalysis and Bioelectrochemistry Lab, Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan, ROC b Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094, China a r t i c l e i n f o Article history: Received 28 January 2016 Received in revised form 12 April 2016 Accepted 16 April 2016 Available online 19 April 2016 Keywords: Graphene oxide Polydopamine Catechol Electro-oxidation Differential pulse voltammetry a b s t r a c t We report a highly sensitive and selective electrochemical catechol (CT) sensor based on gold nanoparti- cles (AuNPs) decorated on graphene oxide@polydopamine (GO@PDA) composite modified glassy carbon electrode. The as-prepared composite materials were characterized by scanning electron microscopy, energy-dispersive X-ray, Raman and Fourier transform infrared spectroscopy. The GO@PDA–AuNPs com- posite modified electrode shows a well-defined redox couple with a better peak to peak separation for CT than that of GO–AuNPs, GO@PDA and GO modified electrodes. Furthermore, GO@PDA–AuNPs composite modified electrode shows an enhanced oxidation peak current response and low oxidation potential for the detection of CT than that of other modified electrodes. Under optimum conditions, the response current of CT at GO@PDA–AuNPs composite modified electrode was linear over the con- centration ranging from 0.3 to 67.55 M with the detection limit of 0.015 M. The sensitivity of the sensor was estimated as 4.66 ± 0.15 AM -1 cm -2 . The GO@PDA–AuNPs composite modified electrode shows its superior selectivity towards CT in the presence of 100-fold additions of potentially active com- pounds including hydroquinone. In addition, the fabricated composite electrode is also applied for the determination of CT in the tap water samples. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Catechol (CT) is an isomer of dihydroxybenzene, has been widely used for different applications, such as production of pesticides, precursor to perfumes and pharmaceuticals [1,2]. The US Environ- mental Protection Agency (EPA) and the European Union (EU) have classified CT as an environmental pollutant due to its high toxicity and low degradability in the ecological environment [3,4]. While, the International Agency for Research on Cancer (IARC) has clas- sified CT as a Group 2B, possible human carcinogen [5]. The high exposure of CT can cause depression of the central nervous system (CNS) and a prolonged rise of blood pressure in animals [6]. Hence, a reliable and accurate detection of CT in environmental samples are more important. Recently, electrochemical methods are widely used for the detection of CT, due to its low cost, quick response, ∗ Corresponding authors. E-mail addresses: smchen78@ms15.hinet.net (S.-M. Chen), xhliu@mail.njust.edu.cn (X.-H. Liu). portability along with high sensitivity compared to available tradi- tional analytical methods [7–9]. So far, different micro and nanomaterials have been successfully used for selective and simultaneous determination of CT [10,11]. In particular, the nanomaterials have promptly used for sensitive detection of CT due to its high surface area and high catalytic activ- ity. For instance, carbon nanomaterials, metal oxides, metal and metal alloy nanoparticles have been widely employed for electro- chemical sensing of CT [12–15]. Among them, graphene oxide (GO) is well-known two-dimensional carbon nanomaterial, has been widely served as a base material for the fabrication of electro- chemical sensors and biosensors [16]. The layered structure, large specific area, amphiphilic in nature and the presence abundant oxy- gen functional groups on the surface of GO has more attractive in electrochemical sensors. However, the electrochemical application of GO is limited due to its insulating properties which are associated with the presence of oxygen functionalities [16]. Hence, differ- ent nanomaterials have been used to improve the electrochemical properties and conductivity of GO [17–20]. Recently, polydopamine (PDA) could easily incorporated with GO and resulting composite widely used for many applications including biological, biomedi- http://dx.doi.org/10.1016/j.snb.2016.04.083 0925-4005/© 2016 Elsevier B.V. All rights reserved.