Electrochimica Acta 85 (2012) 560–565 Contents lists available at SciVerse ScienceDirect Electrochimica Acta jou rn al h om epa ge: www.elsevier.com/locate/electacta Carbon nanotubes modified with antimony nanoparticles: A novel material for electrochemical sensing Fernando C. Moraes a,∗ , Ivana Cesarino a , Vivian Cesarino a , Lucia H. Mascaro b , Sergio A.S. Machado a a Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970 São Carlos, SP, Brazil b Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13565-905 São Carlos, SP, Brazil a r t i c l e i n f o Article history: Received 2 August 2012 Received in revised form 30 August 2012 Accepted 30 August 2012 Available online xxx Keywords: Carbon nanotubes Antimony nanoparticles Bisphenol A a b s t r a c t In this study, a novel material for the electrochemical determination of bisphenol A using a nanocomposite based on multi-walled carbon nanotubes modified with antimony nanoparticles has been investigated. The morphology, structure, and electrochemical performance of the nanocomposite electrodes were characterised by field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, and cyclic voltammetry. A scan rate study and electrochemical impedance spectroscopy showed that the bisphenol A oxidation product is adsorbed on nanocomposite electrode surface. Differential pulse voltammetry in phosphate buffer solution at pH 6, allowed the development of a method to determine bisphenol A levels in the range of 0.5–5.0 mol L -1 , with a detection limit of 5.24 nmol L -1 (1.19 g L -1 ). © 2012 Elsevier Ltd. All rights reserved. 1. Introduction Recently, the development of versatile materials to modify electrode surfaces has been the target of numerous studies in envi- ronmental analysis using electrochemical methods. One of the most widely used materials for surface modification is carbon nanotubes (CNTs). The use of CNTs in electrochemical sensors is due to their unique properties, such as high chemical stability, good electri- cal conductivity, high surface–volume ratio, and high adsorption capacity [1]. Furthermore, the high surface area of CNTs and the presence of functional groups anchored onto them make these materials an excellent support to be modified with several species. These species include: single stranded DNA [2], enzymes [3], metal- lic complexes [4], and conducting polymers [5]. Also, CNTs have the ability to support metallic nanoparticles (NPs) [6]. Such modifica- tion can increase the sensitivity, selectivity, and reproducibility of the developed electrochemical sensor [7]. Metallic NPs constitute a class of smart materials that exhibit physical and chemical properties including a high surface area to volume ratio, optical properties, semiconductor behaviour, and electrocatalysis. These properties are dependent on the metal nature, particle size and microstructure [8]. It has been observed that the nanocomposites formed from the combination of CNTs and NPs show the excellent catalytic properties of NPs without losing any of the electronic properties of CNTs and has a high ∗ Corresponding author. Tel.: +55 16 3373 9924. E-mail address: fcmoraes@hotmail.com (F.C. Moraes). surface area, which allows an increase in the sensitivity of the sen- sor. In addition, such material can be used as a support for the attachment for modifiers species, such as biological material, metal complexes, conducting polymers and even other types of metallic nanoparticles. Recent studies described the use the nanocomposites (CNTs–NPs) in electroanalysis, as shown in the following examples: a non-enzymatic glucose sensor based on copper nanoparticles [9], the determination of l-dopa in the presence of uric and ascorbic acids via gold AuNP self-assembled CNTs [10], and the detection of arsenic using Pt–Fe (III) nanoparticle-modified CNTs [11]. Antimony based electrodes have growing attention in electro- chemical area due to intrinsic properties, such as negative over potential to hydrogen evolution, large scan potential range, can be used in acid solutions, and present a low stripping current signal for itself [12]. Also Sb exhibits similar properties as bismuth and can act as a “mercury-free” electrode in heavy metals stripping anal- ysis [13]. Among these characteristics there are great number of reports describing the use of electrodes based on antimony, includ- ing: Sb powder-modified carbon paste electrodes for determination of heavy metals [14], amorphous carbon-coated Sn–Sb particles as anode material for lithium-ion batteries [15] and Sb-film elec- trode plated over glassy carbon electrode for determination of sulfasalazine [16]. The nanocomposite based on carbon materials (graphite, carbon nanotubes and graphene) and SbNPs is widely used in anode for lithium ion batteries, due to the non-crystalline microstructure of the SbNPs, which allows a stepwise lithium insertion mechanism that can improve the stability of the electrode [17,18]. However 0013-4686/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.electacta.2012.08.123