Functionalized β-cyclodextrin based potentiometric sensor for naproxen determination

Potentiometric sensors based on neutral 6-cyclodextrins: (2-hydroxypropyl)-beta-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin, heptakis(2,3,6-tri-O-benzoyl)-beta-cyclodextrin and anionic beta-cyclodextrin: (2-hydroxy-3-N,N,N-trimethylamino)propyl-beta-cyclodextrin chloride for naproxen are described. Inclusion complexes of naproxen with the above-mentioned cyclodextrins were studied using IR spectroscopy. The electrode surface was made from PVC membranes doped with the appropriate beta-cyclodextrin as ionophores and quaternary ammonium chlorides as positive charge additives that were dispersed in plasticizers. The optimum membrane contains heptakis(2,3,6-tri-O-benzoyl)-beta-cyclodextrin, o-nitrophenyloctyl ether and tetraoctyl ammonium chloride as a lipophilic salt. The electrode is characterized by a Nernstian response slope of -59.0 +/- 0.5 mV decade(-1) over the linear range of 5.0 x 10(-5)-1.0 x 10(-2) mol L-1 and the detection limit 1.0 x 10(-5) mol L-1, as well as the response time 10 s. It can be used in the pH range 6.2-8.5 for 10 months without any considerable deterioration. Incorporation of beta-cyclodextrins improved the electrode selectivity towards naproxen ions from several inorganic and organic interferents and some common drug excipients due to concovalent interactions (host molecule-guest molecule). The notable advantages of the naproxen-selective electrode include its high sensitivity, high selectivity, cost-effectiveness as well as accurate and comfortable application in drug analysis and milk samples. (C) 2015 Published by Elsevier B.V.