Abstract
Two parallel plate cells have been designed for use with an RF admittance bridge to investigate the permittivity of aqueous solutions of biological interest in the frequency range 1-100 MHz. A simple substitutional technique is used to correct for inductance and any second order effects in the apparatus. The versatility of the apparatus is illustrated by the achievement of +or-0.2 in the permittivity for aqueous solutions of conductivity up to 2.5*10-2 Omega -1 m-1. The performance of the bridge is demonstrated with results taken on ethane diol and on solutions of human low density lipoproteins (LDL).