Anionic surfactants are high-foaming active compounds. When dissociate in aqueous solutions, they form organic anions and reduce surface tension. They are well dispersed in water, and used in powder detergents and liquid detergents. Anionic surfactants can be analyzed by using titration methods, spectrophotometric methods, chromatographic methods and by flow injection analysis. Titration methods are based on the forming of ion associates (ion pairs) between anionic surfactants and cationic titrants. Ion-pairs are formed from oppositely charged ions associated by Coulomb interactions in concentrated electrolyte solutions. Ion-selective electrodes are electrochemical sensors that are designed for the potentiometric determination of analytes. The precipitate of ion pair dimethyldioctadecylammonium tetraphenylborate (DMDODA–TPB) was formed by dissolving and evaporating of dimethyldioctadecylammonium chloride (DMDODAC) and sodium tetraphenylborate (NaTPB) solutions. The ion pair was then extracted, purified and isolated. The new synthesized material DMDODA-TPB has been tested as a sensor material in potentiometric titration of anionic surfactants. Standard solution of cetylpyridinium chloride (CPC) at concentration of 4 x 10-3 moldm-3 was used as a titrant and a solution of sodium dodecylsulfate (NaDDS) at concentration of 4 x 10-3 moldm-3 was used as the analyte.