Biosensors and Bioelectronics 24 (2009) 2305–2311 Contents lists available at ScienceDirect Biosensors and Bioelectronics journal homepage: www.elsevier.com/locate/bios The development of a MIP-optosensor for the detection of monoamine naphthalenes in drinking water Angel Valero-Navarro a , Alfonso Salinas-Castillo b , Jorge F. Fernández-Sánchez a,∗ , Antonio Segura-Carretero a , Ricardo Mallavia b , Alberto Fernández-Gutiérrez a,∗ a Department of Analytical Chemistry, University of Granada, c/Fuentenueva s/n, 18071 Granada, Spain 1 b Institute of Molecular and Cellular Biology, University Miguel Hernandez, Elche, Spain article info Article history: Received 2 July 2008 Received in revised form 3 October 2008 Accepted 27 November 2008 Available online 7 December 2008 Keywords: Molecular imprinting Fluorescence optosensor Flow injection Naphthalene compounds Water analysis abstract To enhance the advantages of fluorescent flow-through sensing for drinking water we have designed a novel sensing matrix based on molecularly imprinted polymers (MIPs). The synergic combination of a tailor-made MIP recognition with a selective room temperature fluorescence detection is a novel concept for optosensing devices and is assessed here for the simple and selective determination of pollutants in water. We describe a simple approach to preparing synthetic receptors for monoamine naphthalene com- pounds (MA-NCs) using non-covalent molecular imprinting techniques and naphthalene as template. We examine in detail the binding characteristics of the imprinted polymer and describe the flow-through sensor of MA-NCs by solid-surface fluorescence. Its detection limits for recognizing 1-naphthylamine (1-NA) and 2-naphthylamine (2-NA) separately are 26 ng mL -1 and 50 ng mL -1 , respectively, and it also determines 1-NA and 2-NA simultaneously with a detection limit of 45 ng mL -1 . All the instrumental, chemical and flow variables were carefully optimized and an interference study was carried out to demonstrate its applicability and selectivity. Finally, we applied it to the analysis of 1-NA and 2-NA in tap and mineral waters, obtaining a 98% average recovery rate. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Contamination of surface water and groundwater with aromatic compounds is one of the most serious environmental problems that humans face today. Therefore the efficient detection of aromatic compounds in waste streams has taken on increasing environ- mental concern (Lee and Ku, 1996; Liu et al., 2003). Owing to their acute toxicity and poor biodegradation, 1-naphthylamine (1- NA) and 2-naphthylamine (2-NA), both monoamine naphthalene compounds (MA-NCs), are top-priority contaminants and also the most important substructures of potentially carcinogenic pollu- tants discharged from pharmaceutical, dyestuff, photographic and agrochemical industries (Zhu and Chen, 2000; Li et al., 2001) and cigarette smoke (Stabbert et al., 2003). Despite growing demands for reliable sensors, few methods can be used to detect chemical agents quickly at the level required by the Environmental Protection Agency (EPA) and other inter- ∗ Corresponding authors. Tel.: +34 958 248593; fax: +34 958 249510. E-mail addresses: jffernan@ugr.es (J.F. Fernández-Sánchez), albertof@ugr.es (A. Fernández-Gutiérrez). 1 www.ugr.es/local/fqm297. national organizations. Technologies currently being used, such as gas chromatography–mass spectroscopy (GC–MS) and high- performance liquid chromatography (HPLC), require large, non- portable, expensive experimental devices and often call for exten- sive analytic procedures (Black et al., 1994; Jenkins and Bae, 2005). Table 1 shows an overview of the proposed methods for determining MA-NCs in water together with the advantages and disadvantages of the novel technology described in this work. The combination of flow-injection with detection on opti- cally active surfaces packed in a flow-through cell (optosensor) (Fernández-Sánchez et al., 2003, 2004) has proved to offer impor- tant advantages due to its high sensitivity and selectivity, precision, simplicity, speed and low cost (Casado Terrones et al., 2005). Fur- ther developments of these optosensing techniques have shortened analysis time considerably and reduced costs for routine environ- mental control. Molecular imprinting is a known polymerization technique that prepares synthetic polymers with recognition sites for target ana- lytes (Haupt and Mosbach, 2000; Haupt, 2001; Merkoci and Alegret, 2002). Molecularly imprinted polymers (MIPs) are made by synthe- sizing highly cross-linked polymers in the presence of “printing” molecules (templates). After removal of the template, the poly- mer can be used as a selective medium for the template molecule 0956-5663/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.bios.2008.11.022