SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW AND ON-LINE REDUCTION OF SELENIUM(VI) TO SELENIUM(IV) WITH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC D

摘要

Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species, Selenate (Se-VI) was reduced on-line to selenite (Se-IV) by mixing the CE effluent with concentrated HCl, A microporous PTFE tube was used as a gas-liquid separator to eliminate the (ArCl)-Ar-40-Cl-37 and (ArCl)-Ar-40-Cl-35 interference from Se-77 and As-75, respectively, The direction of the electroosmotic flow during CE was reversed with hydrodynamic pressure, which allowed increased freedom of buffer choice, For conventional pressure injection, method detection limits for Se-IV and Se-VI based on seven replicate injections were 10 and 24 pg, respectively, Recoveries of Se-IV and Se-VI in drinking mater were measured. [References: 35]