Abstract: A method of determining the concentration of a component of interest within a fluid (22) within a container (24) includes determining a permittivity of the fluid, determining a conductivity of the fluid and determining the concentration of the component of interest based on a direct relationship between the determined permittivity and the determined conductivity. An example sensor for making such a concentration determination includes a capacitor portion (26) and control electronics (30) that operate the capacitor in a first mode for making the permittivity determination and a second mode for making the conductivity determination. An example data set (32) includes at least one three dimensional polynomial that describes a relationship between permittivity, conductivity and temperature for a particular concentration value. A disclosed example is well suited for making urea concentration level determinations.