OXYGEN SENSOR VIA THE QUENCHING OF ROOM-TEMPERATURE PHOSPHORESCENCE OF PERDEUTERATED PHENANTHRENE ADSORBED ON WHATMAN 1PS FILTER-PAPER

Perdeuterated phenanthrene (d-phen) exhibits strong room-temperature p hosphorescence (RTP) when adsorbed on Whatman 1PS filter paper. An oxy gen sensor was developed that depends on oxygen quenching of RTP inten sity of adsorbed d-phen. The system designed employed a continuous flo w of nitrogen or nitrogen-air onto the adsorbed phosphor. The sensor i s simple to prepare and needs no elaborate fabrication procedure, but did show a somewhat drifting baseline for successive determinations of oxygen. Nevertheless, very good reproducibility was achieved with the RTP quenching data by measuring the RTP intensities just before and a t the end of each oxygen determination. The calibration plots gave a n onlinear relationship over the entire range of oxygen (0-21%). However , a linear range was obtained up to 1.10% oxygen. A detection limit of 0.09% oxygen in dry nitrogen was acquired. Also, carbon dioxide was f ound to have a minimal effect on the RTP quenching. Thus, oxygen could be measured accurately in relatively large amounts of carbon dioxide. The performance of the oxygen sensor was evaluated by comparing data obtained with a commercial electrochemical trace oxygen analyzer. Also , additional information on the quenching phenomena for this system wa s obtained from the RTP lifetime data acquired at various oxygen conte nts. (C) 1998 Elsevier Science B.V. All rights reserved.