Slurry-based procedures to determine chromium, nickel and vanadium in complex matrices by ETAAS

Two slurry-based ETAAS methodologies are compared to determine directly Cr, Ni and V in coal fly ash, soils and sediments: current slurry analysis (USS) and 'slurry extraction' (SE). Slurries for USS-ETAAS were prepared in 0.5% HNO3. HF and HNO3 were evaluated as chemical modifiers. HF was the extractant for the SE-ETAAS approach. A unique slurry-based procedure to measure Cr, Ni and V could not be established. Cr concentrations up to 100 mu g g(-1) were accurately determined by USS (0.5% HNO3; lambda = 429.0 nm; LOD = 0.35 mu g g(-1)) whereas higher contents required the SE procedure (sample grinding, 30% HF; LOD = 0.02 mu g g(-1)). Both methods were appropriate to determine Ni (LOD = 0.11 and 0.08 mu g g(-1), for USS and SE, respectively). V was satisfactorily quantified only with the USS approach (LOD=0.80 mu g g(-1)). (c) 2005 Elsevier B.V All rights reserved.