Determination of gallium in human urine by supercritical carbon dioxide extraction and graphite furnace atomic absorption spectrometry

This study presents supercritical carbon dioxide (scCO(2)) extraction as an inherently safer and cleaner sample treatment method for identifying trace gallium in urine samples. Extraction is performed in the presence of a fluorinated beta-diketones chelating agent, 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione (HFOD), by unmodified scCO(2). Quantitative extractions are conducted at 80 C and 20.7 MPa with 15 min static plus 15 min dynamic extractions, and are followed by analysis via graphite furnace atomic absorption spectroscopy (GFAAS). The proposed procedure is successfully applied to determine the concentrations of gallium in real urine samples spiked with various levels of gallium with satisfactory recoveries of 90.8-100.3% (n = 6) and relative standard deviations <10%. A standard reference material (SRM), Seronorm(TM) Trace Elements Urine, is used to validate the accuracy of the proposed method. (C) 2008 Elsevier B.V. All rights reserved.