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BackgroundIn spite of the fact that terbium is one of the rarest elements in the Earth’s crust, it is frequently used for the production of high technological materials. At the result, an effective combination of sample preparation procedure and detection method for terbium ions in different matrices is highly required. The solid-phase extraction procedure with natural Transcarpathian clinoptilolite thermally activated at 350 °C was used to preconcentrate trace amounts of terbium ions in aqueous solutions for a final spectrophotometric determination with arsenazo III.ResultsThermogravimetric investigations confirmed the existence of relations between changes that appeared during dehydratation of calcined zeolite and its sorption affinity. Since the maximum of sorption capacity towards terbium was observed at pH 8.25, a borate buffer medium (2.5 · 10−4 М) was used to maintain ionic force and solution acidity. Terbium was quantitatively removed from the solid-phase extraction column with a 1.0 M solution of sodium chloride (pH 2.5). The linearity of the proposed method was evaluated in the range of 2.5-200 ng · mL−1 with detection limit 0.75 ng · mL−1.ConclusionsDue to acceptable recoveries (93.3–102.0 %) and RSD values (6–7.1) from spiked tap water, the developed method can be successfully applied for the determination of trace amounts of terbium ions in the presence of major components of water.Graphical abstractSorption of terbium(III) ions on clinoptilolite

Abstract:The Slovak-Czech spirit distilled from Sorbus domestica was analyzed by GCxGC with headspace solid phase microextraction and liquid-liquid extraction. Two column combinations, nonpolar × medium-polar and polar × medium-polar were tested. The second column setup provided more exploited 2D separation space with better distribution of peaks in chromatogram. Effects of the first column on the elution order of γ-lactones, benzyl esters, and unsaturated aldehydes in the second separation were observed. More than 500 compounds were detected; nearly 100 were confirmed with standards.

In this study, Na-modified Transcarpathian clinoptilolite was used for preconcentration of trace amounts of terbium(III) ions from aqueous solutions. The sorbent was characterized by thermogravimetric analysis. The influence of the preliminary thermal treatment on the sorption activity of Na-modified clinoptilolite was thoroughly investigated. In addition, it was found that such characteristics of the solution as the terbium concentration, acidity, and ion strength have an effect on the sorption capacity of the zeolite in dynamic conditions. The optimum pH range of the solution was found to be 8.8-9.0. A preliminary thermal treatment of Na-clinoptilolite in the temperature range 475-700°C increased the sorption capacity of the sorbent. 7M nitric acid, 6M hydrochloric acid, and 1M NaCl solutions were identified as effective desorbents of terbium(III) ions from Na-clinoptilolite. Furthermore, the influence of the most common ions on the uptake capacity of the sorbent was evaluated.