title: Measurement/data-processing method to improve the ruggedness of membrane-based sensors: Application to amperometric oxygen sensor.
abstract: This paper describes alternative measurement and data-processing approaches that can reduce effects of experimental variables on results obtained with a membrane-based sensor for oxygen. In the new approaches, the membrane-based sensor is first equilibrated with the sample solution, after which a polarizing voltage is applied and current vs. time data are recorded as the response decays toward a steady-state condition. Current vs. time data are then processed by a fixed-time option and an integration option designed to determine the charge corresponding to the total amount of oxygen inside the membrane when a polarizing voltage is applied. The current measured at a fixed time and the total charge varied linearly with oxygen concentration between 0.05 and 0.26 mmol l(-1). Pooled relative standard deviations (N = 35) for the measurement/data-processing step were near 0.4% for the new pre-equilibrium options compared to a value of 0.3% for the steady-state option. Dependencies of the pre-equilibrium options on membrane thickness and stirring rate in the most sensitive regions were at least two orders of magnitude smaller than for the steady-state option.
authors.forename: S
authors.initials: S
authors.lastname: Williams
authors.forename: H L
authors.initials: HL
authors.lastname: Pardue
authors.forename: C E
authors.initials: CE
authors.lastname: Uhegbu
authors.forename: A M
authors.initials: AM
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: Studley