Kevin A. Francesconi

A new arsenic-containing betaine, trimethyl(2-carboxy- ethyl)arsonium inner salt 2, has been identified in fish muscle tissue by liquid chromatography–mass spectrometry.

A large scale extract of the brown alga Fucus serratus was found to contain four arsenosugars (1–4) together with traces of dimethylarsinate (DMA) and arsenate by HPLC-ICP-MS. The extract was divided into 1500 equal subsamples which were then freeze-dried and stored at –18 °C. The homogeneity of this population of subsamples was established by random sampling and quantification of total arsenic by ICP-MS (1.22 µg As ±3.2%, mean ± RSD, n = 32) and hydride generation AAS (1.27 µg As ±2.0%, n = 32), and by quantification with HPLC-ICP-MS of the individual arsenic species in 10 subsamples: arsenosugar 1, 0.10 µg As ±3.6%; arsenosugar 2, 0.086 µg As ±2.9%; arsenosugar 3, 0.62 µg As ±3.8%; arsenosugar 4, 0.40 µg As ±3.1%; dimethylarsinate, 0.005 µg As ±20%; and arsenate ca. 0.001 µg As. The identity of the arsenosugars was confirmed by LC–electrospray (ES) MS with variable fragmenter voltage which provided simultaneous elemental and molecular detection. LC-ESMS was also used to quantify the four arsenosugars, producing values within 5% (2, 3 and 4) or 14% (1) of the ICP-MS data. The subsamples of Fucus extract provide a homogeneous source of natural material containing arsenosugars for use in arsenic speciation studies.

Article ANNOUNCEMENTS was published on April 1, 1997 in the journal Main Group Metal Chemistry (volume 20, issue 4).