Nafion stabilized ibuprofen–gold nanostructures modified screen printed electrode as arsenic(III) sensor Syeda Sara Hassan a,c , Sirajuddin a,⇑ , Amber Rehana Solangi a , Tasneem Gul Kazi a , Muhammad Siddique Kalhoro b , Yasmeen Junejo a , Zulfiqar Ali Tagar a , Nazar Hussain Kalwar a a National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan b Institute of Physics, University of Sindh, Jamshoro 76080, Pakistan c School of Chemistry, Monash University, Australia article info Article history: Received 13 March 2012 Received in revised form 10 July 2012 Accepted 10 July 2012 Available online 20 July 2012 Keywords: Ibuprofen–gold nanoflowers Screen printed electrode Nafion As(III) Water samples abstract Time dependant synthesis of ibuprofen derived gold nanoflowers/nanotructures (Ibu-AuPNFs/Ibu-AuNSs) was carried out via heating the mixture of ibuprofen and gold chloride (HAuCl 4 ) at constant temperature. Characterization studies revealed the interaction of gold nanoparticles (AuNps) with ibuprofen and the changes in their size and shape. The product formed at heating time of 1, 10, 20 and 30 min was exam- ined for arsenic (As(III)) sensing after adsorption at screen printed electrode (SPE) using cyclic voltamme- try (CV) as determining mode. The product formed at 10 min heating performed the best results. The stability of the Ibu-AuNSs at electrode was greatly modified by applying nafion as binder and stabilizing agent. A linear calibration plot was observed for As(III) in the range of 0.1–1800 ppb with lower detection limit (LDL) of 0.018 ppb and regression coefficient (r) of 0.9998 under optimized conditions. The sensor was highly reproducible with relative standard deviation (RSD) of 1.9% for n = 15 and proved very selec- tive for As(III) with no appreciable interference in the presence of various ions. The sensor was success- fully employed for As(III) monitoring in various types of water samples. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Gold nanoparticles (AuNps) have been employed in diverse fields such as electronics, sensors and catalysis [1] owing to their fascinating size dependant properties and higher stability. AuNps are easy to synthesize with controlled size and morphology. They demonstrate significant changes in optical and other properties re- lated to change in size, and can be functionalized by attaching pos- itively charged molecules to their surface [2]. AuNps have been capped with antibiotics [3–5] and small organic molecules like captopril [6] and folic acid [7]. Synthesis of AuNps in the form of flowers or flower-like structures such as confeito-like, fluorescent nanoflowers (NFs) and NSs (wires, plates, flowers, needles and core–shells) has been reported in the literature [8–14]. Several re- ports mentioned that porous NSs play key role in various chemical reactions. Various chemical properties such as sensing, catalysis, energy storage, and synthesis are only effective when porosity is an integral part of the NSs [15]. The use of AuNps or AuNSs as sens- ing materials for the assessment of toxic elements is of primary significance in terms of environmental monitoring and control strategies due to their catalytic potential. One of several toxic ele- ments of great environmental concern is As(III) which is responsi- ble for producing various types of cancers in humans [16]. It has been mentioned that inorganic As(III) is 10 and 70 times more toxic than inorganic As(V) and organic As(V) species respectively [17]. Hence it is extremely desirable to select a highly sensitive, selective and simple analytical technique for monitoring As(III) in the environmental samples. Different techniques employed for As(III) determination in the environment include, Electro-Thermal Atomic Absorption Spectrometry (ETAAS) [16,18], Inductively Cou- pled Plasma Mass Spectroscopy (ICP-MS) [19] and Electro-analysis [20]. The later technique is superior to others in terms of facile methodology for sample preparation, low cost of instruments, sim- plicity in operation and excellent sensitivity. The determination of As(III) by voltammetry using spherical AuNps modified electrodes has been cited elsewhere [21–22] however no report is available regarding the use of composite porous AuNSs for the mentioned task. In our previous work [23] we used ibuprofen derived silver nanoparticles modified glassy carbon as highly selective and sensi- tive sensor for Pb(II) at ultra-trace level. Here we report the fabri- cation of various composite AuNSs and PNFs via time dependant hydrothermal reaction with interesting morphology using ibupro- fen as new reducing as well as capping agent. Furthermore, these NSs have been employed as sensor for the ultra-trace level deter- mination of As(III) using SPE platform with nafion as stabilizing 1572-6657/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jelechem.2012.07.006 ⇑ Corresponding author. Tel.: +92 921 3429; fax: +92 921 3431. E-mail address: drsiraj03@yahoo.com ( Sirajuddin). Journal of Electroanalytical Chemistry 682 (2012) 77–82 Contents lists available at SciVerse ScienceDirect Journal of Electroanalytical Chemistry journal homepage: www.elsevier.com/locate/jelechem