Zirconium and hafnium determination by energy dispersive X-ray fluorescence with solid phase preconcentration

Selective and sensitive spectrophotometric method for the determination of trace amounts of zirconium in environmental and biological samples using 4-chloro-N-(2,6-dimethylphenyl)-2-hydroxy-5-sulfamoylbenzamide

A simple, selective and sensitive spectrophotometric method for the determination of trace amounts of Zr(IV) in aqueous samples was performed, based on complexation reaction between Zr(IV) and 4-chloro-N-(2,6-dimethylphenyl)-2-hydroxy-5-sulfamoylbenzamide (xipamide). The important analytical parameters and their effects on the reported system were investigated. Zr(IV) react with xipamide in the ratio 1:1 in the pH range 8 to form a complex with an absorption maximum 333 nm. The apparent stability constant (logβ(n)) and the free energy change (ΔG) of formation of the complex was calculated using the results of mole ratio and continuous variation methods. Beer's law was obeyed in the concentration range 0.2-3.6 μg/mL. For more accurate analysis, Ringbom optimum concentration range was found from 0.3 to 3.5 μg/mL. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. Taking a constant concentration of Zr(IV) and determining its concentration in the presence of large number of foreign ions tested the effect of foreign ions. The practical applicability of the elaborated method was examined using for determination of mentioned ion in water samples, biological, plant leaves and soil samples where excellent agreements between reported and obtained results were achieved. The relative standard deviation (n=6) were 0.195%. The precision and accuracy of the results were comparable via F and t test at the 95% confidence level.

Simultaneous preconcentration and determination of U(VI), Th(IV), Zr(IV) and Hf(IV) ions in aqueous samples using micelle-mediated extraction coupled to inductively coupled plasma-optical emission spectrometry

A simple cloud point extraction method followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for simultaneous preconcentration and determination of trace amounts of U(VI), Th(IV), Zr(IV) and Hf(IV) ions in aqueous samples. The metal ions in 50 ml of aqueous solution (containing 0.1 M sodium acetate, pH 6.0) were formed complexes with dibenzoylmethane (DBM). Then, Triton X-114 (0.2%, w/v) was added to the solution. By increasing the temperature of the solution up to 50 degrees C, a phase separation occurred. After centrifugation at 4000 rpm for 6 min, the surfactant-rich phase (sediment phase) was diluted with 1.0 ml of 20:80 (v/v) of methanol/1 M HNO(3). The metal ions were then determined using ICP-OES. Finally, the main factors affecting the cloud point extraction were evaluated and optimized. Under optimized conditions, enhancement factors in the range of 37.0-43.6 were obtained. The calibration graphs were linear in the range of 0.5-1500 microg l(-1) for Th and Zr, 0.5-500 microg l(-1) for Hf and 2.5-1240 microg l(-1) for U with correlation coefficients (r(2)) better than 0.9926. The detection limits were between 0.1 and 1.0 microg l(-1) and the R.S.D. values for seven replicates were lower than 6.1%.

Multi-element analysis of pyrite ores using polarized energy-dispersive X-ray fluorescence spectrometry

X-ray fluorescence (XRF) spectrometry is used worldwide in geological material analysis. This study, applies polarized energy-dispersive X-ray fluorescence (PEDXRF) Spectrometer and compares in the samples of Rize-Cayeli and Mardin pyrite ores. The samples of pyrite ore were collected from the Rize and Mardin in Turkey. The prepared samples were analyzed using a PEDXRF spectrometer. The result of the analysis shows the presence of many elements including rare-earth elements (from Na to Th). The accuracy and precision of the technique for chemical analysis is demonstrated by analyzing USGS standards, GEOL, GBW 7109 and GBW-7309 sediment.

Simultaneous determination of Zr(IV) and Hf(IV) by CE using precolumn complexation with a [PW11O39]7− ligand

A CE method was developed for the simultaneous determination of Zr(IV) and Hf(IV) at trace levels. A lacunary Keggin-type [PW(11)O(39)](7-) ligand reacted quantitatively with a mixture of trace amounts of Zr(IV) and Hf(IV) to form the so-called ternary Keggin-type anions [P(Zr(IV)W(11))O(40)](5-) and [P(Hf(IV)W(11))O(40)](5-) in 0.010 M monochloroacetate buffer (pH 2.2). Since both ternary anions possessed different electrophoretic mobilities and high molar absorptivities in the UV region, Zr(IV) and Hf(IV) were determined simultaneously with direct UV detection at 258 nm. Each peak height was linearly dependent on the concentration of Zr(IV) or Hf(IV) in the range of 5.0x10(-7)-1.0x10(-5) M; a detection limit of 2x10(-7) M was achieved. The utility of the proposed CE method was demonstrated for the simultaneous determination of Zr(IV) and Hf(IV) in natural water samples with satisfactory results.

Cloud point extraction and simultaneous determination of zirconium and hafnium using ICP-OES

In the present study a simple versatile separation method using cloud point procedure for extraction of trace levels of zirconium and hafnium is proposed. The extraction of analytes from aqueous samples was performed in the presence of quinalizarine as chelating agent and Triton X-114 as a non-ionic surfactant. After phase separation, the surfactant-rich phase was diluted with 30% (v/v) propanol solution containing 1 mol l(-1) HNO3. Then, the enriched analytes in the surfactant-rich phase were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The different variables affecting the complexation and extraction conditions were optimized. Under the optimum conditions (i.e. 3.4 x 10(-5) mol l(-1) quinalizarine, 0.1% (w/v) Triton X-114, 55 degrees C equilibrium temperature) the calibration graphs were linear in the range of 0.5-1000 mug l(-1) with detection limits (DLs) of 0.26 and 0.31 microg l(-1) for Zr and Hf, respectively. Under the presence of foreign ions no significant interference was observed. The precision (%RSD) for 8 replicate determinations at 200 microg l(-1) of Zr and Hf was better than 2.9% and the enrichment factors were obtained as 38.9 and 35.8 for Zr and Hf, respectively. Finally, the proposed method was successfully utilized for the determination of these cations in water and alloy samples.