Speciation of organoarsenic compounds by polypyrrole-coated capillary in-tube solid phase microextraction coupled with liquid chromatography/electrospray ionization mass spectrometry

In-tube solid phase microextraction (SPME) is an on-line extraction techniq ue for compounds in aqueous samples, in which analytes are extracted and co ncentrated from the sample directly into a coated capillary by repeated asp irate/dispense steps. In this paper, a polypyrrole (PPY) coated capillary a nd several commercially available capillaries (used for GC separation) were used to examine their extraction efficiencies to the organoarsenic compoun ds studied. Compared with commercial capillaries that were currently used f or in-tube SPME, the PPY coated capillary has shown better extraction effic iency to most of the compounds studied, especially to the anionic species, due to the inherent multi-functionality of pyrrole polymer. For the first t ime, this PPY coated capillary has been used for automated in-tube SPME and speciation of organoarsenic species in aqueous samples when coupled with l iquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). Organoarsenic compounds in water samples and arsenobetaine in a certified reference material (DORM-2) were analyzed by this method. (C) 2000 Elsevier Science B.V. All rights reserved.