A novel, single-step LC-ELSD method to characterize the aliphatic fraction of natural waxes

Natural waxes are high melting substances composed mainly of wax esters, fatty alcohols, fatty acids and hydrocarbons. Their industrial application for food remains challenging due to variations in both proportions of these substance classes and their respective molecular composition. The LC-ELSD method presented here enables a single-step quantification of aliphatic compounds in natural waxes without derivatization. Covering carbon numbers (CN) from 18 to over 56, the relevant ranges for these classes are covered. The method is described in detail, with particular focus on ELSD calibration considering individual responses of different substance classes, CNs and dilutions. Calibration data of 35 individual components was transformed to derive universal parameters. LC analysis of standards, GC-FID and literature data on natural waxes were used for validation. Analyses of beeswax, sunflower, rice bran, candelilla and carnauba wax show good agreement, demonstrating both the accuracy and utility of the method for the analysis of wax composition.