Improvement of a gas chromatographic method for the analysis of iminosugars and other bioactive carbohydrates

• Operating conditions are optimized for improvement of GC analysis of iminosugars and inositols.
• Injection temperature was relevant for reproducible analysis of target bioactives.
• Sensitivity required was achieved by GC-FID and GC–MS (SIM mode) methods.
• Iminosugar and inositol contents of mulberry, buckwheat and hyacinth are reported.

The analysis of derivatised iminosugars and other bioactive low molecular weight carbohydrates present at low concentrations in different vegetable extracts (hyacinth, mulberry and buckwheat) required the improvement of a previously developed gas chromatographic method. Among the different parameters optimized, the temperature of the injection port, evaluated for the first time, resulted to be the most important. Thus, 240 °C was chosen as a tradeoff to achieve the required volatility, to avoid degradation and to provide symmetric peaks for bioactive carbohydrates highly retained such as glycosyl inositols. GC–MS operating under selective ion monitoring (SIM) acquisition mode and GC-FID provided limits of detection and quantitation for the target compounds of 0.2 and 0.7 ng g−1 and of 1 and 3 ng g−1 on average, respectively. Therefore, both methodologies could be considered appropriate to extend the range of quantitation of these bioactives.