GC-ECD Method for Determination of Glucosidically Bound Aroma Precursors in Fresh Tea Leaves

The possibility of using GC-ECD to determine glucosidically bound aroma precursors was investigated. Five beta-d-glucopyranosides were derivatized with N-methyl-bis(trifluoroacetamide) (MBTFA) and then determined by GC-ECD, which showed these mono-glycosides (glucosides) could be separated and identified by GC. Repeatability, sensitivity and stability were tested, relative standard deviation (RSD) was in the range of 0.55-5.9%, the limit of detection (LOD) was lower than 10(-3) mu g mL(-1), and the standard mixture was stable within 3 days (stored at 4 A degrees C, peak areas RSD < 3%). Application of the developed derivatization and determination method to the fresh tea leaves showed that the glucosides could be accurately quantified (using phenyl beta-d-glucopyranoside as internal standard). Because of its high sensitivity, the developed method was suitable for the determination of glucosides in fresh tea leaves.