Analysis of Metabolite in Root of Eichhornia crassipes Exposed to Uranium Using iEESI-MS

The metabolic response in the roots of Eichhornia crassipes (water hyacinth) to uranium exposure was studied by internal extractive electrospray ionization mass spectrometry (iEESI-MS). Using a mixture of methanol and water (V∶V=1∶1) as iEESI extractive solution， chemical composition in the roots of water hyacinth samples was profiled in mass scan range of m/z 50-400 under the positive ion detection mode. Using collision-induced dissociation (CID) mode of analysis, metabolites including glycine, asparagine, histidine, choline, indole acetic acid, and eleven aldehyde were detected. The histidine signal shows a significant increase with uranium concentration. Interestingly, water hyacinth root becomes black in color upon 10-day exposure to the 40 μg/mL solution of uranium. This work offers a new approach to study the secondary metabolites of water hyacinth under uranium exposure at the molecular level.