Many chemical sensors and biosensors rely on chemical, biochemical and electrochemical reactions involving oxygen for the detection of the targeted substance. Due to the usually rapid consumption of oxygen by chemical, biochemical or electrochemical reactions and the low rate of oxygen dissolution, the test sample is often in a state of oxygen depletion during the test. This is particularly true if the rate of chemical, biochemical or electrochemical reactions is relatively high. With the drive to develop sensors having a faster response, i.e. shorter measuring cycle, oxygen depletion became a more serious problem. This research had been aimed at the development of oxygen-enhanced membrane assemblies suitable for use in sensors and other devices. Thus, oxygen-enhanced zeolite molecular sieves were included in the membrane assemblies. The oxygen was pre-adsorbed/entrapped on/into the zeolite. Results have shown that desirable levels of "oxygen-enhancement" were achieved, such that effective sensors could be developed. (c) 2005 Elsevier B.V. All rights reserved.