Background correction errors for lead in the presence of phosphate with Zeeman graphite furnace atomic absorption spectrometry

Abstract

Background overcorrection problems with lead in the presence of phosphate in Zeeman graphite furnace atomic absorption spectrometry are investigated. Results show that the overcorrection is not affected by changing the atomization temperature in the furnace program, but is significantly reduced by decreasing the strength of the magnetic field. This observation further supports the assumption that the background overcorrection is caused by the presence of a molecular species (such as PO) formed during the heating process having molecular absorption bands which are subject to Zeeman-effect splitting. The overcorrection error can be diminished by deceasing the amount of phosphate or by replacing the standard transverse-heated graphite atomizer (THGA) tube with an end-capped tube. An accurate method for the determination of Pb in bone using a transverse heated furnace (a P-E 4100ZL) is described.