Hyperbranched macromolecules and methods are described for selectively filtering contaminants such as anions from water and non-aqueous solutions, particularly in the presence of competing contaminants including other anions. Structurally, the system includes a base unit with a rotation head mounted thereon. To facilitate the interpolation, transmission times are preset over the plurality of measurement periods in accordance with a distribution such that the time position of the reception time varies within the histogram over the plurality of measurement periods.