In this paper, the capability of sensing low concentrations of glyphosate in water of two interdigital capacitive transducers are analyzed using numerical simulations and measurements. Each microwave sensor is analyzed using the surface electric field produced at the resonance frequency. In addition, the reflection coefficient of each transducer submerged in water with glyphosate is measured and compared with distilled water. Prepared samples with concentrations of 1ppm/L (1 part per million over a liter of distilled water) are used for the experimental tests.