Photochemical removal of headspace oxygen by a singlet oxygen reaction

A new method is described for removing low levels of oxygen from enclosed atmospheres. The scavenging medium is a film of polymer such as ethyl cellulose or cellulose acetate which contains a sensitising dye and a singlet oxygen acceptor. The acceptor reacts with singlet oxygen formed by the sensitising action of the dye when illuminated. It is shown that the scavenging rate depends on the oxygen permeability of the polymer and on the dye concentration. Removal of oxygen to the detection limit of 0.03 % oxygen is achieved using erythrosin and difurfurylidinepentaerythritol in ethyl cellulose and in cellulose acetate. Potential applications include removal of oxygen from nitrogen‐flushed packages of oxygen‐sensitive foods, essences and chemicals, as well as from vessels for anaerobic microbiology.