Abstract:In this work, magnetic ZnFe2O4 nanotubes (ZFONTs) were used as a dispersive micro- solid phase extraction adsorbent for the separation and preconcentration of Au(III), Pd(II), and Pt(IV) and determination by inductively coupled plasma mass spectrometry. The experimental results showed that Au(III), Pd(II), and Pt(IV) can be adsorbed quantitatively on the ZFONTs in the pH range of 1.0–5.0, and then eluted completely with 1.0 mL of 1.5% thiourea in 0.5 mol L-1 HNO3 solution. No carryover was observed in the next analysis. Separation of the sorbent from the aqueous phase was carried out by an external magnet to avoid the time-consuming column passing or filtration/centrifugation steps. The parameters influencing the preconcentration and determination of the analytes were examined in detail. Under the optimized conditions, the detection limits of this method were 0.35, 0.17, and 0.64 pg mL-1 for Au, Pd, and Pt, respectively. Precision expressed as the relative standard deviation was less than 6.0% (n= 9, c=1.0 ng mL-1). The developed method was applied to the determination of trace/ultra-trace Au, Pd, and Pt in biological and environmental certified reference materials, and the determined values were in good agreement with the certified values.

Abstract:In this study, Cu and Zn isotopic measurements were optimized using a large-geometry high-resolution multiple collector inductively coupled plasma mass spectrometer. A single-column anion-exchange separation of Cu and Zn from igneous rocks was performed using a strong anion resin AG-MP-1M. The Cu and Zn isotopic compositions were calibrated by a sample standard bracketing method, while a Cu internal element spike was also used to correct for mass bias in the Zn measurements. A series of experiments were developed to evaluate the influence of various parameters on the isotopic measurements of Cu and Zn. Acid molarity, matrix (Na, Ti, Mg, and Ni), and residual HF and HCl could significantly affect the accuracy and precision of the results. The long-term external precision was better than ± 0.04‰ (2SD) for both the δ65Cu and δ66Zn. The Cu and Zn isotopic compositions of all igneous rock standards measured in this study agree well with previously published data within uncertainties.

Abstract:A comparative evaluation was carried out to determine the trace metallic constituents in nuclear-grade BeO by D.C. arc carrier distillation and inductively coupled plasma atomic emission spectrometry. D.C. arc carrier distillation is accomplished by physical separation of the major matrix to avoid interference, while ICP-AES employs the solution route because chemical separation of the major matrix is preferred. The method was optimized for Ca, Fe, Mg, Mn, Si, Na, Li, Al, B, Cd, Cr, Cu, Ni, and Zn at minor and trace levels and was optimized using multiple standards and validated using synthetic samples. The analytical performance for both techniques, including detection limits, sensitivity, linear dynamic range, etc., was compared. Though both techniques were found to be suit- able for analysis of nuclear-grade BeO samples, some differences were observed. ICP-AES provides better analytical performance, while D.C. arc requires less sample handling, minimizes process pickup, and results in less toxic expossure in the laboratory.

Abstract:A D.C. arc carrier distillation atomic emission spectrometry based analytical method was developed for the determination of 20 metallic impurities at the trace level. A suitable composition of the carrier gas (5% AgCl) was optimized to sweep away the trace metallic constituents into the arc, leaving the refractory nuclear material matrix inside the electrode to avoid spectral interference from the emission-rich major matrix. The method was optimized by using a suitable choice of interference-free analytical lines for the trace elements with desired analytical performance, including detection limts, linear dynamic range, and sensitivity. The method was validated using synthetic samples analyzed against U3O8 standards as well as 30% PuO2 mixed oxide standards. Using the optimized methods, actual U-Pu-Zr alloy samples were analyzed, and the method was found to be satisfactory.

Abstract:nsitive enrichment method is presented for the determination of palladium (II) in water and environmental samples using deep eutectic solvent-based airassisted emulsification liquid-liquid microextraction (DES-AA- ELLME) and flame atomic absorp- tion spectrometry for analysis. In this procedure, the Pd(II) extraction was obtained using 2-hydroxy- 3-methoxybenzaldehyde thiosemicarbazone (HMBATSC) a complexing agent, tetrahydrofuran (THF) and choline chloride- phenol as emulsifier, and extraction solvents, respectively. The various analytical parameters, including type and molar ratio of the deep eutectic solvent, pH, amount of ligand, and pulling and pushing of the syringe, were studied and optimized. In the experiments, the optimal conditions, analytical characteristics of the investigated method and the limit of detection (1.2 μg L?1), relative standard deviation (3.6 %), linear range (4 to 500 μg L?1), and preconcentration factor (70) were measured. The accuracy of the DES-AA-ELLME method was confirmed with a certified reference material (NIST SRM 2557 Catalyst). The developed method was satisfactorily applied to real water samples with the standard addition method as well as acid-digested environmental samples.

Abstract:A novel, green, and efficient analytical method was developed for the preconcentration of nickel in spinach samples, prior to the determination by slotted quartz tube (SQT)-flame atomic absorption spectrometry (FAAS). Diphenylcarbazone was employed as the ligand, and a deep eutectic solvent (DES)-based liquid phase microextraction (LPME) was used to enrich the analyte for its determination at trace levels. All parameters of the SQT-FAAS and DES method were systematically optimized to enhance the detection power of conventional FAAS. Under the optimum experimental conditions, the optimized method (DES-LPME-SQT-FAAS) recorded a 60-fold improvement in detection power over the FAAS. The limits of detection and quantification were 3.8 and 12.6 μg L-1, respectively. The calibration plot was linear over a wide concentration range, and the precision for replicate measurements was appreciably high. Nickel was not detected in the spinach samples analyzed, but the spiked recovery tests for three samples yielded results close to 100%, confirming the method’s accuracy and applicability to this type of matrix.