Fiber optic oxygen sensor based on phosphorescence quenching of erythrosinB trapped in silica-gel glasses

Experimental results from a phosphorescence-based fiber-optical oxygen sens or are presented. The optical oxygen sensor module has overall dimensions o f 6 x 6 x 12 mm(3). Erythrosin B immobilized in sol-gel silica, which showe d strong phosphorescence quenching by oxygen, was used in the sensor probe. Oxygen sensing is effective from 0.014 to 600 mbar. On account of the long phosphorescence lifetime (similar to 0.28 ms) and high phosphorescence yie ld (similar to 2%) of erythrosin B in sol-gel silica at room temperature, t he sensitivity of the sensor improves by a factor of 10 as compared to tran sition-metal complex-based optical fiber oxygen sensors. The phosphorescenc e quenching effect is highly selective to oxygen. The sensor is inert to co mmonly found gases such as nitrogen and argon, Time-decay of phosphorescenc e is also studied. (C) 2000 Elsevier Science B.V. All rights reserved.