title: Selective Electrochemical Detection of Ciprofloxacin with a Porous Nafion/Multiwalled Carbon Nanotube Composite Film Electrode.
abstract: This study focuses on the development of electrochemical sensors for the detection of Ciprofloxacin (CFX) in natural waters and wastewater effluents. The sensors are prepared by depositing a layer of multiwalled carbon nanotubes (MWCNTs) dispersed in a porous Nafion film on to a boron-doped diamond (BDD) electrode substrate. The porous-Nafion-MWCNT/BDD electrode enhanced detection of CFX due to selective adsorption, which was accomplished by a combination of electrostatic attraction at -SO3(-) sites in the porous Nafion film and the formation of charge assisted hydrogen bonding between CFX and -COOH MWCNT surface functional groups. By contrast, the bare BDD electrode did not show any activity for CFX oxidation. The sensors were selective for CFX detection in the presence of other antibiotics (i.e., amoxicillin) and other nontarget water constituents (i.e., Cl(-), Ca(2+), humic acid, sodium dodecylbenzenesulfonate, salicylic acid, 4-aminobenzoic acid, and 4-hydroxybenzoic acid). A limit of detection of 5 nM (S/N = 5.04 ± 0.26) in a 0.1 M KH2PO4 supporting electrolyte (pH = 4.5) was obtained using differential pulse voltammetry. The linear dynamic ranges with respect to CFX concentration were 0.005-0.05 μM and 0.05-10 μM, and the sensitivities were 41 ± 5.2 μA μM(-1) and 2.1 ± 0.22 μA μM(-1), respectively. Sensor fouling was observed at high concentrations of some organic compounds such as 1 mM 4-aminobenzoic acid and 4-hydroxybenzoic acid. However, a short cathodic treatment fully restores sensor response. The results indicate that these sensors have application in detecting CFX in natural waters and wastewater effluents.
authors.affiliation: Department of Chemical Engineering, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Pralay
authors.initials: P
authors.lastname: Gayen
authors.affiliation: Department of Chemical Engineering, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Chaplin
mesh_terms: D000327:Adsorption; D001895:Boron / Q000737:chemistry; D002138:Calibration; D002939:Ciprofloxacin / Q000032:analysis*; D018130:Diamond / Q000737:chemistry; D004560:Electricity; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D056951:Photoelectron Spectroscopy; D016062:Porosity; D014865:Waste Disposal, Fluid; D014867:Water / Q000737:chemistry
chemical_list: D005465:Fluorocarbon Polymers; D037742:Nanotubes, Carbon; D014867:Water; C040402:perfluorosulfonic acid; D002939:Ciprofloxacin; D018130:Diamond; D001895:Boron
keywords: MWCNT; charge assisted hydrogen bonding; ciprofloxacin sensor; nafion; wastewater