The Complementary Split Ring Resonator (CSRR) geometry is used in conjunction with a microstrip line to create a device able to measure the electric permittivity of liquids. Simulations and measurements of the S-parameters are performed to correlate the resonance frequency and the permittivity of _ve common samples in order to calibrate the device. Once calibrated, we also provide an estimate of the permittivity of a solution of silver nanoparticles. These measurements are attractive given the limited the noninvasive techniques available for nanomaterial characterization and the lack of results at the microwave range. The results estimate the relative permittivity of the silver nanoparticles Er(Ag-NPS)=101.16 +/- 19.53.