IDENTIFICATION OF INORGANIC, METHYLATED AND HYDRIDE-REFRACTORY ARSENIC SPECIES IN ESTUARINE WATERS - ADVANCES BY ELECTROSPRAY, ES-MS, PYROLYSIS-GC-MS AND HPLC-ICP MS/

Water from the Tagus estuary was concentrated and the concentrates pur ified. The identification of the 'refractory' arsenic compounds was at tempted by ES-MS, pyrolysis-GC-MS and HPLC-ICP-MS. The electrospray (E S) data suggest the presence of arsenobetaine, arsenocholine, methylar sonic acid, whereas dimethylarsinic acid and pyrolysis-GC-MS data sugg est the presence of an arsenocholine-type compound. HPLC-ICP-MS confir med unambiguously the presence of arsenobetaine, methylarsonic acid, d imethylarsinic acid, arsenite and arsenate, and the absence of arsenoc holine, trimethylarsine oxide and ionic tetramethylarsonium.