Two new Thio-Arsenosugars found in Scallops

Chromatographing an aqueous extract of the gonad produced two unknown broad signals at long retention times of ~ 30 and ~54 min. Elution was about two times faster when 3% (v/v) methanol was used in the mobile phase. This unusual retention behaviour was previously observed for thio-arsenosugar-glycerol and thio-arsenosugar-phosphate, leading the researchers to speculate that the unknown signals represented two new thio-arsenosugars. A first indication about the structure of these thio-arsenosugars was obtained when the aqueous extract was treated with hydrogen peroxide. The two unknown signals completely disappeared and the signals for arsenosugar-sulfonate and arsenosugar-sulfate increased significantly.

 

To confirm the presence of thio-arsenosugar-sulfonate (A) and thio-arsenosugar-sulfate (B), the original aqueous extract was spiked with synthetic standards of the two compounds. The spiking experiments produced enhanced undistorted peaks at the retention time of the two unknown compounds indicating their identity with the standards. For further confirmation, the group developed a LC-ESMS method that enabled identification of the two new compounds via their pseudomolecular and fragment ions.

 

By using the optimized method, the researchers confirmed that the thio-arsenosugars are present in fresh samples of the scallop, and are not just formed during storage or sample preparation. Further research is needed to study how these arsenic compounds are produced by living organisms and how they are metabolized by humans.

 

 

 

 Markus Kahn, Reingard Raml, Ernst Schmeisser, Birgit Vallant, Kevin A. Francesconi, Walter Goessler, Two Novel Thio-Arsenosugars in Scallops Identified with HPLC-ICPMS and HPLC-ESMS, Environ. Chem., 2/3 (2005) 171-176.

 

 

 

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last time modified: March 17, 2010