Determination of benzalkonium chloride in wet wipes by using a validated capillary electrophoresis method

Benzalkonium chloride (BAC), which is a mixture of C₈ and C₁₈ alkylbenzyldimethylammonium chlorides, has an important biocide character and is used in many cosmetics, especially wet wipes, as a preservative and/or antibacterial agent. The concentration range of BAC is 0.005–0.5 % and it is an irritant substance when used at high concentrations. Thus, the concentration of BAC should be carefully monitored in commercial products intended for skin use. In this study, a capillary electrophoresis (CE) analysis method for BAC quantification was developed. The quantitative analysis was carried out by the external standard method. The electrophoretic separation was performed by using 75 mM (pH 6.0) phosphate buffer solution containing 30% acetonitrile as the electrolyte. The separation voltage was 10 kV and the temperature was held at 18°C. Samples were introduced into the capillary column hydrodynamically using 50.0-mbar pressure over a 3-s period. The developed method was validated and applied on samples prepared by wringing out antibacterial wet wipes containing BAC without any further extraction. The linearity of the method was controlled by applying the Mandel test. The limit of detection (LOD) values for the developed method were 0.313 and 0.309 µg/ml and the limit of quantification (LOQ) values were 1.042 and 1.029 µg/ml for C₁₀ and C₁₂ derivatives, respectively.