Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 13: Posters: Imaging and Superresolution Optical Microscopy
BP 13.4: Poster
Montag, 16. März 2015, 17:30–19:30, Poster A
Calibration of the diffusion coefficients of the FCS standard Rhodamine 6G in aqueous solutions — •Günter Majer — MPI for Intelligent Systems, Stuttgart, Germany
Precise diffusion measurements of rhodamine 6G (Rh6G) dissolved in D2O at various concentrations were carried out in the temperature range from 280 to 320 K using pulsed field gradient nuclear magnetic resonance (PFG-NMR). For the diffusion studies at low Rh6G concentrations, a water suppression PFG-NMR sequence was applied. The temperature and concentration dependent diffusion coefficients of Rh6G can be used as calibration references in fluorescence correlation spectroscopy (FCS). Besides measuring the diffusivity of Rh6G, the diffusion coefficient of the solvent in the same system could be determined in parallel by PFG-NMR as the resonances of water and Rh6G are well separated in the 1H NMR spectrum. The isotope effect of the solvent on the diffusion coefficient is determined by FCS measurements on Rh6G dissolved in both D2O and H2O.