A study on the separation of lipophilic quaternary ammonium cations in NACE coupled with contactless conductivity detection (NACE-C4D) is presented. The suitability of different salts dissolved in various organic solvents as running electrolytes in NACE-C4D was investigated. A solvent mixture of methanol/acetonitrile at a ratio of 90%:10% v/v showed the best results. Deoxycholic acid sodium salt as BGE was found to provide exceptional high stability with low baseline noise that leads to highest S/N ratios for the target analytes among all BGEs tested. Under the optimum conditions, capillaries with different internal diameters were examined and an id of 50 mu m was found to give best detection sensitivity. The proposed method was validated and showed good linearity in the range from 2.5 to 200 mu M, low limits of detection (0.10.7 mu M) and acceptable reproducibility of peak area (intraday RSD 0.10.7%, n = 3; interday RSD 5.99.4%, n = 3).