Authors: Carlos Bendicho, MTC de Loos-Vollebregt
Journal: Spectrochimica Acta Part B, 45: 695-710, 06/1990
A method for extraction of slurries has been developed for the analysis of siliceous materials by graphite furnace atomic absorption spectrometry (GFAAS) with Zeeman background correction. The different materials are powdered and suspended in water containing 3% HF. The preparation of the sample is carried out in autosampler cups and the slurries are stirred by passing a flow of argon through them. The argon flow achieves effective mixing of the slurry and removes part of the silicon as silicon fluoride. The analyte is extracted into the aqueous component of the slurry and consequently the precision is improved. Homogeneous slurries are obtained without the use of stabilizing or dispersing agents. Stabilized temperature platform furnace (STPF) conditions and calibration against aqueous standards have been used for the determination of Cu, Co, Cr, Mn, Fe and Ni in the NIST standard reference materials SRM 1003a, SRM 610, SRM 612, SRM 614 and in quartz. The results of the slurry extraction procedure have been compared with the conventional approach of acid digestion of the sample materials.