Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Novel fluorene-based supramolecular sensor for selective detection of amoxicillin in water and blood Kiramat Shah a, ⁎ , Erum Hassan b , Farid Ahmed a , Itrat Anis b , Muhammad Rabnawaz c , Muhammad Raza Shah a, ⁎ a International Center for Chemical and Biological Sciences, H.E.J. Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan b Department of Chemistry, University of Karachi, Karachi 75270, Pakistan c School of Packaging, Michigan State University, 448 Wilson Road, East Lansing, MI 48824-1223, United States of America (USA) ARTICLE INFO Keywords: Fluorescence spectroscopy Molecular recognition Supramolecular hosts Amoxicillin ABSTRACT Synthesis, characterization and molecular recognition properties of fluorene based supramolecular cleft 1 is reported. The cleft molecule 1 was prepared in a single-step with good yield (85% yield), by linking Fluorene with 1-ethyl piperazine. The cleft molecule 1 was carefully characterized using various spectroscopic techniques such as NMR and mass spectrometry. The supramolecular interaction of cleft 1 with amoxicillin, 6APA, aspirin, captopril, cefotaxime, ceftriaxone, cefuroxime, diclofenac, penicillin, and cephradine was evaluated by fluorescent spectroscopy. The molecular recognition studies showed that amoxicillin selectively binds with cleft 1 in the presence of other drugs. The analytical method developed for the supramolecular interaction of molecular cleft 1 and amoxicillin was validated at varying pH, concentration and temperature during recognition process. Job's plots indicated that the stochiometry of the interactions between the cleft 1 and the amoxicillin was 1:1. 1. Introduction The key process in many biological processes is the molecular recognition. For instance, in organisms the reactions catalyzed by enzymes are based on recognition that takes place between the host (catalyst) and guest (substrate) (Setny et al., 2013). The synthesis of artificial molecular sensor has got significant importance to mimic the biological processes. These artificial sensors have been used as a chemosensor for the detection of varied range of species mainly charged ions, (Sahin and Yilmaz, 2012) neutral analytes, (Czarnik, 1994) globular proteins,(Rakshit et al., 2013) and organic molecules like resorcinol, nicotine and cotinine. (Antwi‐Boampong et al., 2014; Bell and Hext, 2004; Goutam and Iyer, 2015). These chemosensors have been used in environmental, clinical and biological fields, because of their high selectivity, sensitivity, highly efficient binding behaviour and low cast of preparation. (Ahmad et al., 2015; Sharma et al., 2015). Due to the high degree of sensitivity for the analyte detection, fluorosensors have got particular importance among different classes of chemosensors (Khan et al., 2015). For the quantitative determination and efficient detection of various target species, fluorescent chemosen- sors are powerful tools (Han et al., 2010). There are several advantages of fluorescence based detection over other analytical methods. For instance specificity, high sensitivity and real time monitoring with fast reaction time (Lee et al., 2010). An excellent fluorescent sensor generally contains three important components: namely a fluorophore, a binding-recognition unit, and a signal conducting mechanism (Yang et al., 2010). One of the most commonly used antibacterial drugs is amoxicillin (i.e., D-α-amino-p-hydroxybenzylpenicillin trihydrate) (Goodman, 1996), (James et al., 1993). Worldwide this antibacterial drug is used for the treatment of humans as well as agricultural livestock to protect them against various diseases and also to enhance its food production and growth. (Bergamini et al., 2006). Due to the worldwide clinical as well as biological and pharmaceutical use of amoxicillin, methods for is quantifications in the environment are important. For the detection and quantification of amoxicillin several methods such as spectrophoto- metric, (Mohamed, 2001; Pasamontes and Callao, 2004; Salem, 2004; Salem and Saleh, 2002) high-performance liquid chromatography (HPLC), (Liu et al., 2011) fluorometry, (Ma et al., 1999) atomic absorption spectrophotometry, (Li et al., 2000) chromatography, (Aghazadeh and Kazemifard, 2001) mass spectrometry (Wen et al., 2008), flow injection chemi-luminescence, (Fuwei et al., 2010) and electrochemical techniques. (Fouladgar et al., 2011) are available. However, some of these methods have poor sensitivity while most of http://dx.doi.org/10.1016/j.ecoenv.2017.03.003 Received 11 October 2016; Received in revised form 28 February 2017; Accepted 6 March 2017 ⁎ Corresponding authors. E-mail addresses: kiramat4s@gmail.com (K. Shah), raza.shah@iccs.edu (M.R. Shah). Ecotoxicology and Environmental Safety 141 (2017) 25–29 0147-6513/ © 2017 Published by Elsevier Inc. MARK