A comparison of alternative sample preparation procedures for the analysis of swainsonine using LC-MS/MS

Introduction: Swainsonine, a polyhydroxy indolizidine alkaloid and known glycosidase inhibitor, is found in a number of different plants that cause a lysosomal storage disease known as locoism in the western USA. Most recently swainsonine has been analysed by LC-MS/MS after sample extraction and preparation from ion-exchange resins.

Objective: To compare previously published sample preparation procedures with several new alternative procedures to provide methods using either commercially available solid-phase extraction equipment or procedures which significantly reduce sample preparation time.

Methodology: A previously reported and validated sample preparation method using ion-exchange resin was compared with methods using a commercially available solid-phase extraction cartridge, a solvent partitioning procedure or a single solvent extraction procedure using one of two solvents. Twenty different plant samples of varying swainsonine concentrations were prepared in triplicate and analysed by LC-MS/MS. The measured concentration of swainsonine was then statistically compared between methods.

Results: There were no statistically significant differences found between four of the five different sample preparation methods tested.

Conclusion: A commercially available SPE cartridge can be used to replace the previously used ion-exchange resin for swainsonine analysis. For very rapid analyses the SPE procedure can be eliminated and a simple, single solvent extraction step used for sample preparation.