title: Electrochemical sensor for simultaneous determination of herbicide MCPA and its metabolite 4-chloro-2-methylphenol. Application to photodegradation environmental monitoring.
abstract: The development and application of a polyaniline/carbon nanotube (CNT) cyclodextrin matrix (PANI-β-CD/MWCNT)-based electrochemical sensor for the quantitative determination of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) and its main transformation product 4-chloro-2-methylphenol in natural waters are described. A simple cyclic voltammetry-based electrochemical methodology, in phosphate buffer solution at pH 6.0, was used to develop a method to determine both MCPA and 4-chloro-2-methylphenol, without any previous extraction or derivatization steps. A linear concentration range (10 to 50 μmol L(-1)) and detection limits of 1.1 and 1.9 μmol L(-1), respectively, were achieved using optimized cyclic voltammetric parameters. The proposed method was successfully applied to the determination of MCPA and 4-chloro-2-methylphenol in natural water samples with satisfactory recoveries (94 to 107%) and in good agreement with the results obtained by an established high-performance liquid chromatography technique, no significant differences being found between the methods. Interferences from ionic species and other herbicides used for broad-leaf weed control were shown to be small. The newly developed methodology was also successfully applied to MCPA photodegradation environmental studies.
authors.affiliation: Departamento de Engenharia Química, Instituto Superior de Engenharia do Porto (ISEP), Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072, Porto, Portugal.
authors.forename: V
authors.initials: V
authors.lastname: Rahemi
authors.forename: J M P J
authors.initials: JM
authors.lastname: Garrido
authors.forename: F
authors.initials: F
authors.lastname: Borges
authors.forename: C M A
authors.initials: CM
authors.lastname: Brett
authors.forename: E M P J
authors.initials: EM
authors.lastname: Garrido
mesh_terms: D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000032:analysis* / Q000737:chemistry; D000814:Aniline Compounds; D002851:Chromatography, High Pressure Liquid; D003408:Cresols / Q000032:analysis* / Q000737:chemistry; D003505:Cyclodextrins; D055664:Electrochemical Techniques; D004566:Electrodes; D004784:Environmental Monitoring / Q000379:methods*; D006540:Herbicides / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D037742:Nanotubes, Carbon / Q000032:analysis; D010782:Photolysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000814:Aniline Compounds; D003408:Cresols; D003505:Cyclodextrins; D006540:Herbicides; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; C416807:polyaniline; C019292:4-chloro-2-cresol; D008456:2-Methyl-4-chlorophenoxyacetic Acid