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 technique for compounds in aqueous samples, in which analytes are extracted and concentrated from the sample directly into a coated capillary by repeated aspirate/dispense steps. In this paper, a polypyrrole (PPY) coated capillary and several commercially available capillaries (used for GC separation) were used to examine their extraction efficiencies to the organoarsenic compounds studied. Compared with commercial capillaries that were currently used for in-tube SPME, the PPY coated capillary has shown better extraction efficiency to most of the compounds studied, especially to the anionic species, due to the inherent multi-functionality of pyrrole polymer. For the first time, this PPY coated capillary has been used for automated in-tube SPME and speciation of organoarsenic species in aqueous samples when coupled with liquid 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.