SIMULTANEOUS SPECIATION OF REDOX SPECIES OF ARSENIC AND SELENIUM USING AN ANION-EXCHANGE MICROBORE COLUMN COUPLED WITH A MICRO-CONCENTRIC NEBULIZER AND AN INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETER AS DETECTOR

Speciation methods for trace metals in the environment need rapid and accurate analyses, The simultaneous determination of redox species of arsenic (As-III and As-V) and selenium (Se-IV and Se-VI) has been carr ied out by coupling a microbore column with a micro-concentric nebuliz er (MCN) and inductively coupled plasma mass spectrometry (ICP-MS), Th e MCN, with its ability to nebulize liquids at low flow rates, was ada pted to a small bore (2 mm id) microbore anion-exchange column, After optimizing the parameters of the MCN by factorial experimental-design, an evaluation of the separation of redox As and Se species was carrie d out, The method was applied to the determination of the four species in a sample recommended for Se speciation studies, in a spilled natur al water and in polluted soil leachings., No interference of (ArCl)-Ar -40-Cl-35 on As-75 was observed when natural water samples were analyz ed. The method showed good accuracy and repeatability in addition to f acile handling and development. A detection limit of 1 ng ml(-1) was f ound for the arsenic species and 4 ng ml(-1) for the selenium species.