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Ph. D. ThesisPh. D. Thesis 9. Results  All Data Sets9. Results All Data Sets 9.1. Methanol and Ethanol by SPR9.1. Methanol and Ethanol by SPR 9.1.1. Single Analytes9.1.1. Single Analytes
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Ph. D. Thesis
  Abstract
  Table of Contents
  1. Introduction
  2. Theory Fundamentals of the Multivariate Data Analysis
  3. Theory Quantification of the Refrigerants R22 and R134a: Part I
  4. Experiments, Setups and Data Sets
  5. Results Kinetic Measurements
  6. Results Multivariate Calibrations
  7. Results Genetic Algorithm Framework
  8. Results Growing Neural Network Framework
  9. Results All Data Sets
    9.1. Methanol and Ethanol by SPR
      9.1.1. Single Analytes
      9.1.2. Parallel Growing Neural Network Framework
      9.1.3. Sensitivity Analysis
      9.1.4. Brute Force Variable Selection
      9.1.5. Conclusions
    9.2. Methanol, Ethanol and 1-Propanol by SPR
    9.3. Methanol, Ethanol and 1-Propanol by the RIfS Array and the 4l Setup
    9.4. Quaternary Mixtures by the SPR Setup and the RIfS Array
    9.5. Quantification of the Refrigerants R22 and R134a in Mixtures: Part II
  10. Results Various Aspects of the Frameworks and Measurements
  11. Summary and Outlook
  12. References
  13. Acknowledgements
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9.1.1.   Single Analytes

The changes of the resonance wavelength when the device was exposed to alternating sequences of different concentrations of analyte and to synthetic air are shown in figure 15 in section 4.5.2.1 with the shift of the SPR resonance wavelength plotted versus the time and versus the relative saturation pressure of analyte (0 to 0.045). It is visible that 10 seconds of exposure to methanol vapor are enough to reach equilibrium between the methanol vapor and the methanol, which is sorbed into the polycarbonate layer, and thus the resonance wavelength does not change any more. In contrast, even after 120 s of exposure of the polycarbonate layer to ethanol vapor equilibrium has not been reached. However, after 120 s the signals of ethanol are higher than the signals of methanol for the same relative saturation pressure as ethanol has a higher refractive index (nD20 =1.362) than methanol (nD20 =1.329). Since the diffusion of ethanol is slower, the signals at short exposure times are lower compared to methanol.

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