Specificity, accuracy, and interpretation of measurements of ethylene oxide gas concentrations during sterilization using a microwave spectrometer

Publisher Website
Google Scholar
Abstract
This article reports the update in the design of a microwave spectrometer for measuring concentrations of ethylene oxide gas during sterilization. The specificity of the measurement (absorption line at 23.134 GHz) using the spectrometer has been found to be virtually 100%. A great number of calibrations have been conducted in the range of concentrations 100% to 40% of ethylene oxide gas at intervals of −10% in order to determine the accuracy of the spectrometer. It was found that the maximum standard deviation from the regression curve was 1.2% full scale (0%–100%). A mathematical model based on a diffusion equation has been developed and was used to interpret the real time measurement data during sterilization. Numerical simulation using this model has demonstrated that it is possible to predict the dynamic distributions of ethylene oxide concentration within the load being sterilized.