Microwave dielectric characterization of aqueous solutions of tryptophan

Abstract

This paper describes dielectric relaxation in aqueous solutions of tryptophan at different temperatures and concentrations. Time Domain Reflectometry in reflection mode has been used to measure the complex reflection coefficient ρ*(ω) in the frequency range of 10 MHz to 20 GHz. Bilinear calibration method has been used to obtain complex permittivity spectra ∞dot;,(ω) from the complex reflection coefficient. Dielectric parameters i.e. static permittivity and relaxation time were obtained from the complex permittivity spectra using nonlinear least squares fit method. From the values of relaxation time, thermodynamic parameters were obtained. The values of dielectric relaxation parameters increase with an increase in molar concentration of Tryptophan.