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2013|14 Annual Report Fraunhofer IGB

77 Dr. Michael Haupt Phone +49 711 970-4028 michael.haupt@igb.fraunhofer.de Dr. Christian Oehr Phone +49 711 970-4137 christian.oehr@igb.fraunhofer.de References [1] Haupt, M.; Peetsch, A.; Oehr, C. (2009) Elektronen-Spin- Resonanz – Eine Methode zur Bewertung der Radikalaktivität auf photokatalytischen Implantatoberflächen, Vakuum in Forschung und Praxis, Bd. 21, Nr. 6, S. 22 – ​29 [2] Haupt, M.; Barz, J.; Oehr, C. (2008) Creation and recombina- tion of free radicals in fluorocarbon plasma polymers: an electron spin resonance study, Plasma Processes and Polymers, Bd. 5, Nr. 1, S. 33 – ​43 Detection of free radicals and Reactive Oxygen Species (ROS) In order to determine the quantities of radicals, only a few milligrams of solids or powders or a few milliliters of liquids are required. The measurement is performed as a function of time, radiation dose and / ​or temperature after the irradiation. Besides free radicals, we can also quantify reactive oxygen species (ROS) and nitrogen monoxide (NO) in biological sys- tems e.g. cells or blood by means of ESR spectroscopy. Analysis of the antioxidative potential Over and above this, we use ESR spectroscopy to determine the antioxidative effect of antioxidants. Ascorbic acid (Vitamin C), for example, is a radical scavenger. Thanks to its antioxi- dative effect it protects cells from damage. We can detect ascorbic acid radicals generated through the scavenging of undesired radicals by means of ESR spectroscopy. Areas of application Using ESR spectroscopy, we can examine quickly and safely how high the maximum gamma radiation dose has to be so as on the one hand, to kill germs and pathogens and, on the other, to keep the radical load in the product as low as pos- sible. In the following products we quantify the amount of radicals and also detect, as the case may be, the type of radicals: Foods (coffee, malt, cereals, fruit, vegetables, herbs and spices etc.) and food packaging Cosmetics and toiletries Disposable medical products Implants and drugs Pharmaceutical precursors and packaging 1 Sterilization with gamma rays is explicitly recommended for drugs and medical devices. 2 Over time, the quantity of radicals in a gamma- irradiated antibiotic decays, but radicals can still be detected weeks after irradiation. 3 In foods such as cereals gamma rays can kill germs and pathogens. 32 Contacts 2,6E18 ESRsignal[spinnumber / ​g] time [min] 4,6E18 4,4E18 4,2E18 4,0E18 3,8E18 3,6E18 3,4E18 3,2E18 3,0E18 2,8E18 0 1000 2000 3000 4000 5000 6000 7000

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