TY - CHAP A1 - Kirchner, Patrick A1 - Reisert, Steffen A1 - Schöning, Michael Josef T1 - Calorimetric gas sensors for hydrogen peroxide monitoring in aseptic food processes T2 - Gas sensing fundamentals. (Springer Series on Chemical Sensors and Biosensors ; 15) N2 - For the sterilisation of aseptic food packages it is taken advantage of the microbicidal properties of hydrogen peroxide (H2O2). Especially, when applied in vapour phase, it has shown high potential of microbial inactivation. In addition, it offers a high environmental compatibility compared to other chemical sterilisation agents, as it decomposes into oxygen and water, respectively. Due to a lack in sensory detection possibilities, a continuous monitoring of the H2O2 concentration was recently not available. Instead, the sterilisation efficacy is validated using microbiological tests. However, progresses in the development of calorimetric gas sensors during the last 7 years have made it possible to monitor the H2O2 concentration during operation. This chapter deals with the fundamentals of calorimetric gas sensing with special focus on the detection of gaseous hydrogen peroxide. A sensor principle based on a calorimetric differential set-up is described. Special emphasis is given to the sensor design with respect to the operational requirements under field conditions. The state-of-the-art regarding a sensor set-up for the on-line monitoring and secondly, a miniaturised sensor for in-line monitoring are summarised. Furthermore, alternative detection methods and a novel multi-sensor system for the characterisation of aseptic sterilisation processes are described. KW - Calorimetric gas sensor KW - Hydrogen peroxide KW - Multi-sensor system Y1 - 2014 SN - 978-3-642-54518-4 (Print) ; 978-3-642-54519-1 (Online) U6 - http://dx.doi.org/10.1007/5346_2013_51 SP - 279 EP - 309 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Friedrich, Peter A1 - Berger, Jörg A1 - Rysstad, Gunnar A1 - Schöning, Michael Josef A1 - Keusgen, Michael T1 - Realisation of a calorimetric gas sensor on polyimide foil for applications in aseptic food industry JF - Sensors and Actuators B: Chemical N2 - A calorimetric gas sensor is presented for the monitoring of vapour-phase H2O2 at elevated temperature during sterilisation processes in aseptic food industry. The sensor was built up on a flexible polyimide foil (thickness: 25 μm) that has been chosen due to its thermal stability and low thermal conductivity. The sensor set-up consists of two temperature-sensitive platinum thin-film resistances passivated by a layer of SU-8 photo resist and catalytically activated by manganese(IV) oxide. Instead of an active heating structure, the calorimetric sensor utilises the elevated temperature of the evaporated H2O2 aerosol. In an experimental test rig, the sensor has shown a sensitivity of 4.78 °C/(%, v/v) in a H2O2 concentration range of 0%, v/v to 8%, v/v. Furthermore, the sensor possesses the same, unchanged sensor signal even at varied medium temperatures between 210 °C and 270 °C of the gas stream. At flow rates of the gas stream from 8 m3/h to 12 m3/h, the sensor has shown only a slightly reduced sensitivity at a low flow rate of 8 m3/h. The sensor characterisation demonstrates the suitability of the calorimetric gas sensor for monitoring the efficiency of industrial sterilisation processes. KW - Sterilisation process KW - Hydrogen peroxide KW - Polyimide KW - Calorimetric gas sensor Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2011.01.032 SN - 0925-4005 N1 - Part of special issue "Eurosensors XXIV, 2010" VL - 170 SP - 60 EP - 66 PB - Elsevier CY - Amsterdam ER -