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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.

A new sensitive method is described for measuring the permeation and diffusion of oxygen through polymer films. For these measurements an ethyl cellulose film containing 9,10-dimethylanthracene (DMA) and erythrosin may be either tightly sealed between two pieces of sample film in a simple cell or sealed in a pouch made from the test material, and is used to absorb oxygen which has passed through the polymer film sample from the air. On illumination this oxygen is converted by the erythrosin to singlet oxygen which then reacts with the DMA. After an initial scavenging period, the rate of permeation of oxygen under the atmospheric pressure gradient across the film is monitored by determining the rate of disappearance of DMA spectrophotometrically. Es wird eine neue, empfindliche Methode fur die Messung der Durchdringung und Diffusion von Sauerstoff durch Polymerfilme beschrieben. Ein Ethylcellulosefilm, der 9,10-Dimethylanthrazen (DMA) und Erythrosin enthalt, wird fur die Absorption von Sauerstoff verwendet, der aus der Luft durch die Polymerfilmprobe dringt. Bei Belichtung wird der Sauerstoff durch das Erythrosin in die Singulettform uberfuhrt, die dann mit dem DMA reagiert. Nach einer anfanglichen Reinigungsperiode wird die Durchdringungsgeschwindigkeit vom Sauerstoff unter dem atmospharischen Druckgefalle durch den Film verfolgt, indem man die Geschwindigkeit des Verschwindens vom DMA spektrophotometrisch bestimmt. Fur diese Messungen kann der Ethylcellulosefilm entweder in einer einfachen Zelle dicht zwischen zwei Probefilmstucken eingefugt oder in einem Beutel von Probematerial eingeschlossen sein.

The addition of 2–5 ppm of TMTDS (tetramethylthiuramdisulphide) or ziram markedly decreased the shelf life of canned pears, but 1 ppm of these materials had little effect. The addition of trace levels of sulphur or captan to canned pears appeared to increase the shelf life; addition of sodium sulphide appeared to have a negligible effect on shelf life. The shelf life of canned peaches, apricots, pineapple, apples, and citrate solution was also decreased by the addition of 5 ppm TMTDS or ziram. TMTDS and ziram caused pitting of the base steel of the tinplate with little attack on the tin coating. Pitting was not seen in cans containing added sulphur, sulphide, or captan and the rate of corrosion of the tin coating was less than in cans containing no added chemicals. Formation of passive films and reduction of the hydrogen overpotential were considered to be important factors influencing corrosion of cans containing the added agricultural chemicals.