Determination of trace chromium(VI) in drinking water using X-ray fluorescence spectrometry after solid-phase extraction

A new, simple, and selective method for preconcentration and determination of Cr(VI) in aqueous samples. After adsorption in batch mode on Aliquat 336-AC, determinations were made directly on the solid by X-ray fluorescence spectrometry, which had the advantage of not requiring the step of elution of the chromium retained. The enrichment factor was calculated considering that the tablets obtained from 10 mL solution of Cr(VI) (1000 mu g L-1) had a final thickness of 0.64 mm and a diameter of 16.7 mm; the volume deposited on the pellet was 0.14 cm(3). The preconcentration factor obtained was 71-fold, which was highly satisfactory for chromium trace analysis by XRF. Finally, the method was successfully applied to the determination of Cr(VI) in drinking water samples.