An optical oxygen sensor based on the fluorescence quenching of 1-pyrenedecanoic acid chemisorption film was developed. The I-0/I-100 value, where I-0 and I-100 represent the detected fluorescence intensities from a film exposed to 100% argon and 100% oxygen, respectively, of I-pyrenedecanoic acid film is estimated to be 36.6. The 1-pyrenedecanoic acid chemisorption film onto alumina plate is a highly sensitive device for oxygen compared with the other oxygen sensor using pyrene compounds. (C) 2002 Elsevier Science B.V. All rights reserved.