Ion Chromatography Separation of Cotton Surface Melezitose and Raffinose: Entomological vs. Plant Sugars

According to previous studies, certain levels of the carbohydrates melezitose and trehalulose deposited on the surface of cotton are indicative of either whitefly or aphid contamination, which may cause problems during cotton processing.  Obtaining reliable IC values for those surface sugars is paramount in diagnosing a contamination source. Since the plant sugars raffinose and sucrose are isomers of melezitose and trehalulose, respectively, it can be difficult to fully separate them from the entomological sugars via IC, especially when the analysis time is shortened.  An improved IC method has been developed which separates melezitose and raffinose from one another; in total nine sugars were separated using the new method.  By testing the water extracts of five raw cotton samples via our IC method, we have shown decreases in melezitose amounts present, when compared to the previous method.  The difference in melezitose amounts were from separating out the raffinose and another unidentified component from the melezitose peak during IC integration.