Arsenic compounds arsenosugars

Fig. 3. Typical separation of four arsenosugars and DMA by HPLC/ICP-MS using an ODS reversed-phase column at pH 3.2 under conditions described in Ref. 60. The sensitivity and specificity of the detector allows the determination of arsenosugars and other arsenic compounds to be conducted on dilute aqueous extracts of the marine samples.

Arsenobetaine, arsenosugars and arsenocholine are organoarsenicals less toxic for animals and humans than inorganic arsenic compounds, and have been found in certain marine organisms and in seafoods. They are excreted rapidly in urine (about 70% of the dose in 24h) . Natural arsenic is a pure one-isotope element ( As) and had to be labelled with radioactive arsenic for metabolic studies. As has been chosen as the most suitable isotope for tracer investigations. 

Arsenic compounds were determined in the marine lungworm Arenicola marina collected from Odensee Fjord, Denmark [159]. In contrast to most other marine animals, A. marina contained most water-soluble arsenic in inorganic forms, and arsenobetaine 54 was present as a minor constituent (6% only). Other arsenic compounds detected in A. marina were dimethylarsinate 47 (4%), tetramethylarsonium ion 53 (1.5%), arsenocholine 55 (<1%), and two arsenosugars (56, 57, 1% and 3%, respectively). A new arsenobetaine, i.e. trimethylarsoniopropionate (62), previously only reported in fish, was also present in trace amounts (<1%). 

Arsenosugars are the major arsenic compounds in marine algae. They chiefly comprise water-soluble dimethylarsinoyl compounds (see Fig. 2, compounds 1-4 and 6-11), although lipid-soluble derivatives (see Fig. 2, compound 5) and quaternary arsonio analogues (see Fig. 2, compounds 12-14) are also found (4). Although many arsenosugars have been identified in algae, there are only four (see Fig. 2, compounds 1-4) that are commonly found. 

Arsenic compounds in marine plants have not been well studied so far. They appear not to contain arsenosugars (39). 

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