Contents lists available at ScienceDirect Journal of Luminescence journal homepage: www.elsevier.com/locate/jlumin Solvent control bifunctional fluorescence probe for selective detection of Cu 2+ and Hg 2+ via the excimer of pyrenylacetamide subunits Thamon Puangsamlee a , Yordkhuan Tachapermpon a , Peeraporn Kammalun a , Kanjarat Sukrat b , Chantana Wainiphithapong a , Jitnapa Sirirak a , Nantanit Wanichacheva a, ⁎ a Department of Chemistry, Silpakorn University, Nakhon Pathom 73000, Thailand b Chemistry Program, Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000, Thailand ARTICLE INFO Keywords: Copper Mercury Cu 2+ -Selectivity Hg 2+ -Selectivity Excimer Pyrenylacetamide ABSTRACT A new highly sensitive fluorescence sensor having two pyrenylacetamide moieties covalently bound to 2-[4-(2- aminoethylsulfanyl)butylsulfanyl]ethanamine was prepared via the ready synthetic approach using a conven- tional three-step synthesis. Its excimer and its sensing behavior towards metal ions were investigated by fluorescence spectroscopy. The results showed that the sensor exhibited bifunctional behaviors by sensitive sensing toward Cu 2+ in ethanol and offered sensitive sensing toward Cu 2+ and Hg 2+ in aqueous methanol solutions. These high selectivities of the sensor were confirmed by an efficient quenching of the excimer bands of pyrenylacetamide at 480 nm, whereas other ions including Ag + , Ca 2+ , Cd 2+ ,K + , Mn 2+ , Na + , Pb 2+ Zn 2+ , Ba 2+ , Fe 2+ , Li + , Mg 2+ and Co 2+ ions induced small or negligible spectral change. The detection limits of the sensor were approximately 0.6 and 0.8 ppb for Hg 2+ and Cu 2+ , respectively, which were much lower than drinking water permission concentrations by the United States Environmental Protection Agency (U.S. EPA) and World Health Organization (WHO). 1. Introduction In the past decade, the design of new fluorescence chemosensors for determination of metal ions in food and environment is one of the most challenging research area [1–3]. Fluorescence chemosensors are not only nonstructive and rapid method, they are also highly sensitive and highly selective for detections of metal ions, therefore, many fluores- cence chemosensors for metal pollutants including copper and mercury have been developed. Via the reaction between copper ions and di- oxygen, reactive oxygen species (ROS) were formed. These ROS can cause the cellular toxicity which leads to serious neurodegenerative diseases such as Wilson disease and Alzheimer’s disease. On the other hand, mercury is considered a neurotoxin which can cause serious human health problems including DNA damage, mitosis impairment and permanent damage of the central nervous system [4,5]. In the marine system, inorganic mercury (Hg 2+ ) can be transformed to me- thylmercury by bacteria and can further go through biological mem- branes and finally enter into the food chain [6]. Hence, the con- tamination of Cu 2+ and Hg 2+ ions in food and environment are very concerned. The United States Environmental Protection Agency (US EPA) requires the maximum contaminant level goals (MCLG) for Cu 2+ and Hg 2+ in drinking water as 1.3 ppm and 2 ppb, respectively [7]. For the trace-quantity analysis of Cu 2+ and Hg 2+ ions, there are several traditional analytical methods including inductively coupled plasma mass spectrometry [8], atomic absorption spectroscopy [9,10], and electrochemical analysis [11], however these methods often re- quire a large amount of samples, expensive and sophisticated in- strumentations. Fluorescence spectroscopy is one of the most useful technique because it can be used to determine various analyzing agents such as protons (H + ) [12,13], small molecules [14–18], anions [19,20] and cations [21–23] including Cu 2+ and Hg 2+ [23–31]. Moreover, this technique requires small amount of sample (0.2-3 mL), relatively in- expensive, high sensitivity and high selectivity, offers prompt de- termination for real time tracking for the analysis of Cu 2+ and Hg 2+ . Although there were many fluorescent Cu 2+ and Hg 2+ ionophores re- ported such as naphthalimide [32], hydroxyquinoline [33,34], azine [35], cyclams [36–39], pyrazoline [40], and calixarene [41], they were often required difficult multi-steps synthesis, relatively high costs, provide moderated sensitivity and utilized in organic solvents. Hence, the development of simple sensors which could provide high sensitivity or low detection limits for the detection of Cu 2+ and Hg 2+ using less synthetic effort and inexpensive starting materials are remained in great demand. Herein, we have modified a new fluorescence sensor based on 2-(4- (2-aminoethylsulfanyl) butylsulfanyl)ethanamine ligand which con- sisted of sulfur and nitrogen atoms as donor atoms that can self https://doi.org/10.1016/j.jlumin.2017.11.048 Received 19 July 2017; Received in revised form 15 October 2017; Accepted 22 November 2017 ⁎ Corresponding author. Journal of Luminescence 196 (2018) 227–235 Available online 24 November 2017 0022-2313/ © 2017 Elsevier B.V. All rights reserved. T