title: An impedimetric chemical sensor for determination of detergents residues.
abstract: A new impedimetric sensor based on an interdigitated electrode array with electrode digits located at the bottom of microcapillaries formed in silicon dioxide is presented. Microcapillaries are opened at the top, so that in contact with an electrolyte solution the ac current flows close to the surface of the capillary wall from one electrode to another and is significantly affected by changes in the surface conductance at the SiO2/electrolyte interface. Adsorption of detergents on the sensor surface affects the charge distribution in the electrical double layer and thus the surface conductance. These changes are registered by measuring impedance. Effect of surface adsorption of ionic and non-ionic surfactants on the sensor impedance is studied. The sensor is shown to be able to measure commercial detergents residues in a tap water starting from 5 ppm even in solutions with high electrolyte conductivity.
authors.affiliation: Instituto de Microelectronica de Barcelona, Centro Nacional de Microelectronica (CSIC), Campus UAB, 08193 Bellaterra, Barcelona, Spain. Andrei.Bratov@imb-cnm.csic.es
authors.forename: Andrey
authors.initials: A
authors.lastname: Bratov
authors.forename: Natalia
authors.initials: N
authors.lastname: Abramova
authors.forename: Andrey
authors.initials: A
authors.lastname: Ipatov
authors.forename: Angel
authors.initials: A
authors.lastname: Merlos
mesh_terms: D003902:Detergents / Q000032:analysis*; D060766:Drinking Water / Q000737:chemistry*; D017097:Electric Impedance; D055664:Electrochemical Techniques; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry*; D006801:Humans; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D003902:Detergents; D060766:Drinking Water; D004573:Electrolytes; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide