A single-measurement methodology to produce accurate dielectric spectra is developed and validated by measurements on a dilute aqueous suspension containing I mu m polystyrene particles suspended in 0.1 mM KCl. Electrode polarization artifacts in the spectra are eliminated down to the kilohertz frequency regime. Corrected dielectric spectra agree with previously established extrapolation methods and the standard electrokinetic theory. The method is simple yet effective and allows for accurate time-dependent measurements without the need for disassembling and reassembling the dielectric cell.