Arsenic determination with graphite-cloth ribbon in graphite-furnace atomic-absorption spectrometry

The determination of arsenic by atomic-absorption spectrometry with use of a graphite-cloth ribbon placed inside various types of graphite tubes was investigated. It was found that the graphite-cloth ribbon greatly enhances the sensitivity for arsenic and reduces the interferences from various heavy metals, especially when it is placed inside a pyrolytic graphite tube and a nitric acid matrix is used. This is attributed to condensation of arsenic on the ribbon, owing to a temperature lag during the drying and ashing cycles, and to the formation of interlamellar compounds of arsenic with graphite.