title: Highly sensitive CNT composite amperometric sensors integrated in an automated flow system for the determination of free chlorine in waters.
abstract: We report the benefit of using an optimized composite electrode, based on a multiwall carbon nanotubes and epoxy resin, as working electrode in an automated flow system. The optimal composite electrode composition consists in a 10% carbon nanotubes and 90% epoxy resin. This composition provides lower limit of detection and increases the stability and reproducibility of the analytical signal compared to the 20% conventional composition electrodes. Moreover, the standard solutions are on-line prepared with an automated flow system. The integration of the developed carbon nanotube electrodes in the proposed flow system provides a highly sensitive analyzer for free chlorine determination in water down to the 20microgL(-1). The working range was found to be 0.02-4mgL(-1) with an analysis time of 60s. The system sensitivity was maintained into the control limits (+/-2sigma) for one month, with a mean value of -0.146 (+/-0.008) microALmg(-1). Validation of the analytical system has been performed by the successful determination of free chlorine in tap water and swimming pools water samples.
authors.affiliation: Grup de Sensors i Biosensors, Departament de Química, Facultat de Ciències, Edifici C-Nord, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Olivé-Monllau
authors.forename: Ana
authors.initials: A
authors.lastname: Pereira
authors.forename: Jordi
authors.initials: J
authors.lastname: Bartrolí
authors.forename: Mireia
authors.initials: M
authors.lastname: Baeza
authors.forename: Francisco
authors.initials: F
authors.lastname: Céspedes
mesh_terms: D001331:Automation; D002138:Calibration; D002713:Chlorine / Q000032:analysis*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013551:Swimming Pools; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D002713:Chlorine