1. Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstr. 6, DE-38678Clausthal-Zellerfeld, Germany
2. Clausthal University of Technology, Institute of Technical Chemistry, Arnold-Sommerfeld-Str. 4, DE-38678Clausthal-Zellerfeld, Germany
3. Fraunhofer Heinrich-Hertz-Institute, Department Fiber Optical Sensor Systems, Am Stollen 19 H, DE-38640Goslar, Germany