Novel approach for the determination of zirconium by solid-phase spectrophotometry

Solid-phase spectrophotometry was used to determine trace amounts of zirconium[IV] in water, soil, plant materials and ore samples. Zr[IV] was sorbed in a dextran-type lipophilic gel as a complex with 2-(2-benzothiazolylazo)-3-hydroxyphenol. The resin-phase absorbance at 569 and 800 nm was measured directly, allowing determination of Zr in the range 0.25–3.7 μg L−1, with a relative standard deviation of 1.06%. The influence of analytical parameters, including pH, the amounts of 2-(2-benzothiazolylazo)-3-hydroxyphenol and sample volume was investigated. Molar absorptivity was 1.08 × 105, 6.38 × 106, and 1.97 × 107 L mol−1 cm−1 at 100, 500 and 1000 mL, respectively. The limits of detection and quantification of the 500-mL sample method were 150 and 470 ng L−1, respectively, with 40 mg dextran-type lipophilic gel. For a 1000-mL sample, the limits of detection and quantification were 80 and 240 ng L−1, respectively. Increasing the sample volume enhanced the sensitivity. No significant interference from other anions and cations was observed.