Capillary zone electrophoresis in skin fatty acid analysis

The development of a method for analyzing C12-C18 fatty acid alkali salts by capillary zone electrophoresis is described. Organic solvents were added to the aqueous separation buffer to achieve solubility of the fatty acids together with higher temperatures. Detection of these poorly UV absorbing species could be achieved by indirect photometric detection adding a highly UV absorbing co-ion to the separation buffer. Thus detection limits of 6 microM were recorded. The dynamic range of quantitation was limited to 10(1) due to association and micelle formation at higher concentrations. The relative standard deviation of the method was in the range of 4 to 10%. The described method could be successfully applied to the analysis of free fatty acids in human stratum corneum after solid phase extraction of the lipid fraction.