Determination of phosphorus by graphite furnace atomic absorption spectrometry. Part 1. Determination in the absence of a modifier

Abstract

In the absence of a modifier a substantial part of the analyte is lost prior to its atomisation. Phosphorus can, however, be stabilised by reaction with graphite in the condensed phase. Uncoated polycrystalline electrographite offers a much larger number of active carbon sites and hence much more favourable conditions for phosphorus determination than pyrolytic graphite coated tubes. The number of active carbon sites can be further increased if oxygen is added to the argon purge gas during certain stages of thermal pre-treatment. The best characteristic mass values obtained in the absence of a modifier [ca. m_o= 20 ng (0.0044 A s)^–1] are, however, substantially inferior to those in the presence of modifiers.