Investigation into mercury bound to biothiols: structural identification using ESI-ion-trap MS and introduction of a method for their HPLC separation with simultaneous detection by ICP-MS and ESI-MS

Eva Maria Krupp, B. F. Milne, Adrien Mestrot, Andrew Alexander Meharg, Jörg Feldmann

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Mercury in plants or animal tissue is supposed to occur in the form of complexes formed with biologically relevant thiols (biothiols), rather than as free cation. We describe a technique for the separation and molecular identification of mercury and methylmercury complexes derived from their reactions with cysteine (Cys) and glutathione (GS): Hg(Cys)(2), Hg(GS)(2), MeHgCys, MeHgGS. Complexes were characterised by electrospray mass spectrometry (MS) equipped with an ion trap and the fragmentation pattern of MeHgCys was explained by using MP2 and B3LYP calculations, showing the importance of mercury-amine interactions in the gas phase. Chromatographic baseline separation was performed within 10 min with formic acid as the mobile phase on a reversed-phase column. Detection was done by online simultaneous coupling of ES-MS and inductively coupled plasma MS. When the mercury complexes were spiked in real samples (plant extracts), no perturbation of the separation and detection conditions was observed, suggesting that this method is capable of detecting mercury biothiol complexes in plants.

Original languageEnglish
Pages (from-to)1753-1764
Number of pages11
JournalAnalytical and Bioanalytical Chemistry
Issue number7
Early online date24 Feb 2008
Publication statusPublished - Apr 2008


  • mercury
  • methylmercury
  • biothiols
  • high-performance liquid chromatography
  • electrospray mass spectrometry
  • inductively coupled plasma mass spectrometry
  • conformation modelling
  • basis-sets
  • bioaccumulation
  • derivatization
  • toxicology
  • complexes
  • peptides
  • mimicry
  • plants

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