Arsenic in marine organisms: New species and new analytical approaches

Recently two new classes of arsenic species have been identified in marine organisms; thio-arsenic species where the oxygen bonded to arsenic is replaced by a sulphur group and two types of arsenic -lipids, arsenic hydrocarbons and arsenic phospholipids. Here we describe the common species found in marine and HPLC-ICPMS analytical approaches to measure these species. Thio-arsenic species can be separated using C18 reverse phase chromatography with elution with aqueous phosphate buffer. Arsenic lipids can be separated by C8 reverse phase chromatography with gradient elution comprising acetic acid and methanol with gradient elution conditions: 0-25 min, 50%-95% methanol; 25-40 min, 95% methanol. Using gradients, the introduction of methanol directly into the ICPMS spray chamber is required to compensate for the variable amounts of carbon in the mobile phase entering the ICPMS.