Arsenic speciation in tree moss by mass spectrometry based hyphenated techniques

A method based on ion-pair reversed phase high performance liquid chromatography (HPLC) hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) was developed for arsenic speciation in extract of tree moss. Under the optimal conditions, the limit of detection of eight arsenic species including arsenite (As-III), arsenate (As-V), monomethylarsonic acid (MMA), dimethylarsonic acid (DMA), trimethylarsinoxide (TMAO), tetramethylarsonium (Tetra), arsenocholine (AsC) and arsenobetaine (AsB) is between 0.04 and 0.07 ng/mL, with a linear range of 0.2 - 500 ng/mL. Three unknown arsenic species (Unk1, Unk2 and Unk3) and six specific arsenic species (As-III, As-V, DMA, TMAO, Tetra and AsB) were detected in the extract of tree moss. Unk3 was identified as a kind of arsenosugars (2,3-dihydroxypropyl-5-deoxy-5(dimethylarsenoso)furanoside, arsenosugar X) by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-qTOF-MS).