A novel approach for an automated liquid/liquid extraction system—principle and application for the determination of several trace contaminants in highly alloyed steels and base alloys
AbstractA novel automated liquid/liquid extraction system was developed for the determination of trace contaminants in unalloyed, alloyed and highly alloyed steels and super alloys. In the presented batch extraction system the aqueous phase and the non-water miscible organic phase were brought into close phase contact by high-speed stirring with a magnetic stir bar. Iodide complexes of Ag, Bi, Cd, Pb, Sb, Sn, Tl, and Zn were extracted from aqueous steel digests into 4-methylpentan-2-one (MIBK) containing 20 g L−1 trioctylphosphine oxide. Ag, Bi, Cd, Pb, and Tl were extracted quantitatively whereas the extraction yields of Sb, Sn, and Zn were 83%, 61% and 75% respectively. Using high resolution continuum source flame AAS (HR-CS-FAAS) for analyte quantification the method was validated using 21 certified steel reference materials (CRMs).
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Matrix-assisted photochemical vapor generation for determination of trace bismuth in Fe Ni based alloy samples by inductively coupled plasma mass spectrometry
Abstract As the impurities in alloy may affect its mechanical and physical properties, the determination of trace elements is important to ensure the quality of alloy. However, accurate determination of trace impurities in alloy samples is a big challenge due to their complicated matrix and low concentrations. In this work, matrix-assisted photochemical vapor generation (PVG) was developed for the determination of impurity in alloy samples by inductively coupled plasma mass spectrometry (ICPMS). Bismuth was selected as the target element, which is detrimental to the strength of alloy even at very low concentration. The transition ions existed in alloy worked as the “sensitizers” for the efficient PVG of bismuth, and only formic acid and acetic acid were required for the analysis of alloy samples after digestion. This largely reduced the risks of sample contamination and analyte loss in multiple sample pretreatment involved in conventional analytical methods. The PVG efficiency of bismuth was greatly enhanced, making the sensitive and simple determination of trace analytes in alloy samples feasible. The limit of detection (LOD, 3σ) for Bi was found to be 0.4 ng L−1 corresponding to 0.54 ng g−1 for analysis of 0.5 g of alloy sample. A relative standard deviation (RSD) of 1.1% was obtained from seven replicate measurements of 0.5 μg L−1 Bi3+ in sample matrix. The proposed method was successfully applied for the determination of Bi in two certified reference materials (Fe Ni based alloys GBW01621 and GBW01622).
Extraction, separation and spectrophotometric determination of cadmium and mercury using triphenylphosphine oxide and its application to environmental samples.
A method is proposed for the solvent extraction of cadmium and mercury from salicylate media using triphenylphosphine oxide as extractant. The optimum extraction conditions were evaluated from a critical study of the effect of pH, sodium salicylate concentration and the concentration of triphenylphosphine oxide. The probable composition of the species has been deduced from log-log data and an extraction mechanism is suggested. The method has been used to separate zinc, cadmium and mercury from binary and ternary mixtures and for the spectrophotometric determination of mercury or cadmium in environmental samples.