Dual beam near-infrared process analyzers (NIR-O™ and ClearView™ db) can be configured to provide real-time measurement of ethylene oxide (also known as EO or EtO) gas during sterilization cycles. Ethylene oxide is commonly used in the healthcare and pharmaceutical industries as an alternative to steam sterilization or other chemical sterilization methods. For sterilization to occur, a sufficient concentration of EO must be present for an adequate length of time. The efficiency of the process is facilitated by the presence of water vapor or humidity. The concentration of EO required also depends on the temperature of the process. The higher the temperature, the lower the concentration of EO that will be necessary for sterilization to occur. The ability to measure the EO and water vapor concentrations during the complete sterilization cycle provides analytical validation that all sterilization conditions have been met.
Feasibility Study for Real Time Monitoring off ETO
Near-infrared spectra of EO at 30 kPa and water vapor at 22.1 mg/l are shown in Figure 1. These spectra were measured with a Guided Wave NIR-O using a 25 cm pathlength gas probe. Strong EO gas absorbance peaks at 1643 and 1693 nm are easily identified. Water vapor peaks occur at 1362 nm and 1871 nm and do not interfere significantly with the distinct EO peaks. A series of near-infrared spectra collected at varying EO pressures are shown in Figure 2.