This work illustrates a novel technique, high-frequency transmission spectroscopy (HFTS), for the characterization of analyte in aqueous solution. The application of this technique to material characterization is similar traditional impedance spectroscopy (IS) but differs primarily in that HFTS is a measure of transmitted potential through the material (voltage out versus voltage in) rather than its impedance (current out versus voltage in). The material properties explored by HFTS are not limited to effects occurring at the electrode/analyte interface which dominate IS measurements. Additionally, electric network analyzers (ENA), used for the characterization of frequency response, provide spectrum measurement capability over a much higher frequency range than typical impedance instrumentation. In this work, the capability of HFTS is demonstrated using three test cases: electrolyte solutions, carbon nanoparticles in solution, and sulfate latex microparticles in aqueous suspension. The experimental setup consists of a 3D printed liquid test cell, custom design patch antennae, and an off-the shelf ENA with a frequency range of 300 kHz to 500 MHz. The magnitude response of these analytes at various concentrations demonstrated a sensitivity of the measurement on the order of 10 µM. Furthermore, the system shows the ability to distinguish between monovalent and divalent ions and detect changes in radii on the order of 10 pm to 1 µm. Techniques demonstrated in this work have a wide range of potential applications including environmental monitoring, detection of polluting substances (e.g. PFAS) in water, and disease/infection screening.