Determination of sodium chondroitin sulfate in cosmetic products by capillary tube isotachophoresis

Abstract

As a simple analytical method, the capillary tube isotachophoresis was applied to the analysis of sodium chondroitin sulfate (ChnS) in cosmetic products. The best result was obtained with the acidic electrolyte system in which the leading electrolyte contained 0.01 M hydrochloride, β-alanine and Triton X-100 pH 3.2, and the terminal electrolyte contained 0.01 M caproic acid. In order to avoid interferences cosmetic products were extracted by using cetylpyridinium chloride. The recovery of ChnS from known samples was 92.4 % and the method was applicable to the qualitative and quantitative analysis of ChnS in commercial cosmetic products. Advantages of isotachophoresis in this field are as follows. 1) The sample can be injected directly. 2) Multiple ionic components can be analyzed simultaneously.