A method of sterilizing an article by sequentially exposing the article to hydrogen peroxide and ozone is disclosed. The article is exposed under vacuum first to an evaporated aqueous solution of hydrogen peroxide and subsequently to an ozone containing gas. The exposure is carried out without reducing the water vapor content of the sterilization atmosphere, the water vapor content being derived from the aqueous solvent of the hydrogen peroxide solution and from the decomposition of the hydrogen peroxide into water and oxygen. The complete sterilization process is carried out while the chamber remains sealed and without removal of any component of the sterilization atmosphere. For this purpose, the chamber is initially evacuated to a first vacuum pressure sufficient to cause evaporation of the aqueous hydrogen peroxide at the temperature of the chamber atmosphere. The chamber is then sealed for the remainder of the sterilization process and during all sterilant injection cycles. Keeping the chamber sealed and maintaining the hydrogen peroxide and its decomposition products in the chamber for the subsequent ozone sterilization step results in a synergistic increase in the sterilization efficiency and allows for the use of much lower sterilant amounts and sterilization cycle times than would be expected from using hydrogen peroxide and ozone in combination.La presente invención se refiere a una unidad de medición de peróxido de hidrógeno para un esterilizador de peróxido de hidrógeno que tiene un suministro de peróxido de hidrógeno y un vaporizador de peróxido de hidrógeno, la unidad de medición comprendiendo de un cuerpo que define una vía de medición que tiene un volumen fijo y extremos corriente arriba y corriente abajo, el extremo corriente arriba estando conectado únicamente con el suministro de peróxido de hidrógeno, y el extremo corriente abajo estando conectado únicamente con el vaporizador de peróxido de hidrógeno, para que el peróxido de hidrógeno fluya desd
