Solid-phase spectrophotometric determination of trace amounts of vanadium using 2,3-dichloro-6(3-carboxy-2- hydroxynaphthylazo)quinoxaline

Solid-phase spectrophotometry (SPS) has been applied to analysis for trace amounts of vanadium in several environmental water (potable and polluted), biological samples (human blood and urine), and soil samples. Vanadium was sorbed in a styrene-divinylbenzene-type anion-exchanger Dowex 1-X8 as a vanadium--2,3-dichloro-6(3-carboxy-2-hydroxynaphthylazo)quinoxaline. Resin phase absorbances at 606 and 800 nm were measured directly which allowed the determination of vanadium in the range 0.03-2.2 ng ml(-1) with a relative standard deviation (R.S.D.) of 1.4%. The comparison of the SPS method and the gallic acid persulphate method shows that the linearity, analytical sensitivity, and precision were better for the SPS method, and that the latter method has lower detection and quantification limits compared with the gallic acid persulphate method.