Evaluation of modifiers for determination of V in parsley by GF AAS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The thermal behaviour of vanadium in the absence and presence of BaF(2), W and Rh as modifiers were evaluated for the direct determination of V in parsley slurries by GF AAS. For the sequence BaF(2), no modifier, W and Rh, the characteristic masses were 16, 17, 58 and 37 pg, and the RSD were 1.3%, 0.6%, 9.8% and 10.8%, respectively. BaF(2) and absence of modifier furnished the best thermal stability, signal profile, repeatability and characteristic mass. For slurries containing 0.5% (m/v), 0.2% (v/v) HNO(3), 0.05% (v/v) Triton X-100, the pyrolysis and atomisation temperatures were 1700 and 2600 degrees C. respectively. The method was applied for V in digests and slurries and results agreed at 95% confidence level. Spinach and tomato leaves standard reference materials were analysed and results agreed with certified values. Recoveries from 93% to 108% were obtained. The graphite tube lifetime and LOD was 250 firings and 0.94 mu g L(-1), respectively. (C) 2009 Elsevier Ltd. All rights reserved.