Determination of vanadium in soils and sediments by the slurry sampling graphite furnace atomic absorption spectrometry using permanent modifiers

A new analytical procedure for vanadium (V) determination in soils and sediments by the slurry sampling graphite furnace atomic absorption spectrometry (slurry sampling GFAAS) using the mixed permanent modifiers is described. Moreover, the comparison of action of the modifiers based on the iridium (Ir) and carbide-forming elements: tungsten (W) and niobium (Nb) deposited on the graphite tubes is studied, especially in terms of their analytical utility and determination sensitivity. The mechanism of their action was investigated using an X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector (EDX). Finally, the mixture of 0.3 μg of Ir and 0.04 μg of Nb was used for the graphite tube permanent modification. The analytical procedure was optimized on the basis of the data from pyrolysis and atomization temperature curves studies. The results obtained for the four certified reference materials (marine sediments: PACS-1 and MESS-1, lake sediment: SL-1, soil: San Joaquin Soil SRM 2709), using the slurry sampling GFAAS and the standard calibration method, were in good agreement with the certified values. The detection and quantification limits and characteristic mass calculated for the proposed procedure were 0.04 µg/g, 0.16 µg/g and 11.9 pg, respectively. The precision (RSD% less than 8%) and the accuracy of vanadium determination in the soil and sediment samples were acceptable.