Planar amperometric oxygen sensor with improved preconditioning property

The feasibility of enhancing the preconditioning time property of the plana r type amperometric oxygen sensor is investigated. A gas permeable membrane is formulated by incorporating hydrophilic polyurethane (HPU) into a one-c omponent room temperature vulcanizing (RTV) silicone rubber matrix. Planar oxygen sensors are made by forming a recipient hydrogel layer on the base e lectrodes screen printed on a substrate, and by covering the hydrogel layer with a gas permeable membrane. The optimized RTV/HPU (70/30 wt.%) yields a gas permeable membrane with fast water vapor transport that allows for fas t hydration of the inner hydrogel layer, yet is not permeable to chloride i ons that could interfere with oxygen measurements by changing the potential of the inner Ag/AgCl reference electrode. The proposed RTV/HPU-based plana r oxygen sensor is shown to exhibit enhanced preconditioning time property (i.e. time required to reach 95% of the steady-state current = 2 s) with a sensitivity (slope: 1.1 nA/mmHg) and a Linearity (correlation coefficient: 0.999 in the range of 0.6-268 mmHg) that are adequate for dissolved oxygen measurements in physiological samples. (C) 2001 Elsevier Science B.V. All r ights reserved.