A bis-pyrene polyamine receptor for fast optical detection of ketoprofen: synthesis, characterization and application in all-solid-state fluorescent sensors

Here we report on a polyamine receptor L1 bearing pyrene fluorogenic groups for the optical assessment of non-opioid analgesic drug ketoprofen, KP. L1, composed of a diethylenetriamine moiety linked at its extremities to the 1 position of two pyrene units via methylene linkers, gives an emission at 460 nm in water/ethanol 1:1 (v:v) mixture at pH 7, likely due to the excimer formation between the two aromatic groups.. In the presence of KP a salt bridging interaction between the carboxylate group of the analyte and the central ammonium group of L1 induces a redistribution of the acidic protons in the polyamine chain causing a marked increase of the emission. This optical signal was used to detect KP in aqueous media. Inspired by this observation, the properties of all-solid-state optodes with plasticized PVC membranes doped with L1 and deposited on the appropriate solid support material were further tested. The best membrane contained 1wt% of fully protonated L1, plasticized with DOS and doped with 3 equiv. of TDMACl anion-exchanger. It was able to detect KP in 2μM–0.1mM range with a low influence of interfering ions and applied for KP assessment in OkiTask with RSD of 2.1% and recovery of 102%. Moreover, the possibility to low down the KP DL to 0.84 μM (0.21mg/L) through the application of L1 based fluorescent sensor array and chemometrics was shown.