Arsenic speciation in algae

Arsenic speciation in a variety of commercial algal products and a brown alga, Fucus gardneri, collected in Vancouver, B.C., was carried out by using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS)and hydride generation atomic absorption spectrometry (HGAAS). Water-soluble organoarsenic compounds present in commercially available food products made from red algae, brown algae and blue-green algae were analyzed by using HPLC-ICP-MS. By the application of two HPLC columns and two mobile phase conditions, arsenosugars (arsenoribofuranosides) in a variety of algae were identified by comparing the retention times with the organoarsenic compounds previously identified in an oyster tissue standard reference material, NIST 1566a. A commercial brown algal product, kelp powder, was found to contain four different arsenosugars. This product may have potential as a "standard reference material" for identification purposes. A terrestrial blue-green alga, Nostoc commune var flagelliforme, was also analyzed and found to contain an arsenosugar, a compound which was previously known only in marine organisms. The total arsenic content as well as the amounts of water-soluble arsenic compounds in all commercial products were determined by using a continuous flow HGAAS system. Commercial marine algae were found to contain high amounts of total arsenic, from 7.6 μg g⁻¹ to 49.3 μg g⁻¹. The terrestrial product was found to contain only 2.7 μg g⁻¹ of total arsenic.