title: Trace detection of oxygen--ionic liquids in gas sensor design.
abstract: This paper presents a novel electrochemical membrane sensor on basis of ionic liquids for trace analysis of oxygen in gaseous atmospheres. The faradaic response currents for the reduction of oxygen which were obtained by multiple-potential-step-chronoamperometry could be used for real time detection of oxygen down to concentrations of 30 ppm. The theoretical limit of detection was 5 ppm. The simple, non-expensive sensors varied in electrolyte composition and demonstrated a high sensitivity, a rapid response time and an excellent reproducibility at room temperature. Some of them were continuously used for at least one week and first results promise good long term stability. Voltammetric, impedance and oxygen detection studies at temperatures up to 200 °C (in the presence and absence of humidity and CO2) revealed also the limitations of certain ionic liquids for some electrochemical high temperature applications. Application areas of the developed sensors are control and analysis processes of non oxidative and oxygen free atmospheres.
authors.affiliation: Fraunhofer Institut für Chemische Technologie, Joseph-von-Fraunhofer-Str. 7, D-76327 Pfinztal (Berghausen), Germany. Electronic address: norman.baltes@ict.fraunhofer.de.
authors.forename: N
authors.initials: N
authors.lastname: Baltes
authors.forename: F
authors.initials: F
authors.lastname: Beyle
authors.forename: S
authors.initials: S
authors.lastname: Freiner
authors.forename: F
authors.initials: F
authors.lastname: Geier
authors.forename: M
authors.initials: M
authors.lastname: Joos
authors.forename: K
authors.initials: K
authors.lastname: Pinkwart
authors.forename: P
authors.initials: P
authors.lastname: Rabenecker
mesh_terms: D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D057230:Limit of Detection; D010100:Oxygen / Q000032:analysis*; D013696:Temperature
chemical_list: D004573:Electrolytes; D007093:Imidazoles; D052578:Ionic Liquids; D010100:Oxygen
keywords: Electrochemical sensor; Ionic liquids; Oxygen; Temperature behaviour; Tetracyanoborates; Trace analysis