Colorimetric phosphorescence measurements with a color camera for oxygen determination

摘要

We developed a simple oxygen imaging platform with phosphorescent oxygen sensor films to demonstrate a quantitative oxygen determination method utilizing a color CCD camera. Phosphorescence quenching of a luminophore Pt(II) meso-tetrakis (pentafluorophenyl) porphyrin complex (PtTFPP) immobilized in poly (dimethylsiloxane) (PDMS) matrix, is the principal detection mechanism. This sensor material was cast to form a film on the bottom surface of a transparent Petri dish. As levels of dissolved oxygen increased, phosphorescence of the complex decreased, allowing for measurement of oxygen levels which developed in the sensor film. A camera with a charge-coupled device (CCD) was used in conjunction with processing software to quantify oxygen levels colorimetrically. Microscopic images were collected using a CCD camera and stored as a set of red/green/blue (RGB) images. Phosphorescence excitation (390 nm peak) is limited to the blue (B) pixels of the CCD chip, and these values were discarded; while retaining the oxygen-responsive phosphorescence emission (645 nm peak) almost identical with the response range of the red (R) pixels. Red pixel intensity analysis effectively extracts color intensity information, which can be in turn directly related to oxygen contents. Color CCD cameras allow simultaneous acquisition of many types of chemical information by combining the merits of digital imaging with the attributes of spectroscopic measurement. Therefore, use of color CCD cameras is considered as an inexpensive alternative to time-resolved imaging for relatively short-term monitoring.