title: Oxygen sensor design: analysis and correction of problems associated with zero current, stability and structure.
abstract: Membrane-covered polarographic sensors were designed by Leland Clark several decades ago. The membrane covering was a brilliant innovation because it provided an isolation of electrochemical elements from the external environment. These sensors have found a wide range of applications in many aspects of medicine, research and industry but they do not perform well at low oxygen levels because of high and unpredictable zero-current and drift characteristics. The key to overall improved zero-current and stability was a highly improved cathode seal design. Rather than heat-sealing wire into glass microtubing, a high temperature molding procedure was employed. Other improvements involved substantial modifications to the conventional methods of fixing the membrane in place, eliminating all crevices at the periphery of the membrane. This guards against potential contamination, entrapment of gas bubbles and carry over. The present sensor design can operate in gases and liquids with zero current less than 0.02% oxygen.
authors.affiliation: University of Pennsylvania, Radiation Oncology Dep't, 195 John Morgan Bldg., Philadelphia, PA 19104, USA. kochc@mail.med.upenn.edu
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Koch
mesh_terms: D000388:Air; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D007700:Kinetics; D008567:Membranes, Artificial; D010100:Oxygen / Q000032:analysis*; D010313:Partial Pressure
chemical_list: D008567:Membranes, Artificial; D010100:Oxygen