Luminescence ratiometric oxygen sensor based on gadolinium labeled porphyrin and filter paper

Abstract

A fluorescence–phosphorescence ratiometric oxygen sensing system based on gadolinium labeled hematoporphyrin monomethyl ether (Gd-HMME) and filter paper was developed. A compact and simple measurement system was constructed utilizing fiber optoelectronic sensing device. Optical parameter (OP) was defined as the ratio of filter paper background fluorescence to oxygen sensitive Gd-HMME phosphorescence. We demonstrate that the OP is independent of excitation intensity in this ratiometric method. The measured results of oxygen concentration were calibrated and displayed by a Labview-based software. The fluctuation is about 0.1% for a wide range of oxygen concentration above 10% and much less than 0.1% for oxygen concentrations lower than 3%. A detection limit of 0.01% was achieved. The response time was determined to be about 4s. These results indicate that the system we have developed can be used for oxygen detection in the whole range and is especially accurate for very low oxygen concentrations.