In a hydrogen peroxide gas plasma sterilizer, the concentration of the hydrogen peroxide sterilant is an important factor in determining sterilization efficacy. The present application describes sterilizers, and sterilization methods, which use a novel injector-concentrator arrangement. This arrangement provides accurate control of concentration of the liquid-phase hydrogen peroxide, prior to vaporization of the liquid sterilant into the sterilization chamber. This increases the reliability and efficacy of the sterilization cycle.
