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In this study, the potassium adsorption for the purification of crude ammonium perrhenate solutions in the presence of various cheap and available ion exchange resins is reported for the first time. After the resin screening test, the optimum resin (Purolite® C100 resin as a strong acid cation ion exchange resin in the sodium form) was selected for morphological analysis using field emission scanning electron microscopy, which was further examined by energy-dispersive spectroscopy. Moreover, X-ray elemental mapping of the surface of C100 resin revealed homogeneous potassium adsorption. BET and TGA tests confirmed the adsorbed potassium on the C100 resin. Among the isotherm models, the Langmuir isotherm provided the best fit according to the correlation coefficients. The adsorption parameters have been scrutinized, including contact time, initial potassium concentration, temperature, and competitive binary potassium and sodium adsorption. The result of the binary system exhibited a decrease in the potassium adsorption capacity of the resin in the presence of secondary ions due to competition for adsorption sites. Kinetic characteristics of the potassium adsorption process were investigated by pseudo-first-order and pseudo-second-order, intraparticle diffusion, and Elovich models. The adsorption process has been found to match the pseudo-first-order reaction. The continuous/extended experiments and the elution test were also evaluated. [ABSTRACT FROM AUTHOR]

One of the new electrochemical sensors has been devised and fabricated for the highly sensitive determination of venlafaxine on the basis of ZnO nanoflowers (ZnO-NF) as modified materials. Therefore, hydrothermal methods have been used to synthesize zinc oxide nanoflowers. The formation of ZnO nanoflower has been confirmed via Fourier transform infrared (FTIR), XRD, and FESEM. Owing to the ZnO nanoflowers with the greater surface areas to oxidation of venlafaxine, venlafaxine has been sensitively determined with the linear ranges between 0.04 and 475.0 µM and LOD equal to 0.01 µM (S/N = 3). This new technique has been substantially utilized to determine venlafaxine in real samples. [ABSTRACT FROM AUTHOR]

In the present study, we utilized a novel electrochemical sensor for the determination of colchicine in 0.1 M phosphate buffer solution (pH 4.0) using differential pulse voltammetry. 1-butyl-3-methylimidazolium tetrachloroferrate ([Bmim]FeCl4) was synthesized, investigated by FT-IR, Raman and UV–Vis spectrometer and applied as magnetic ionic liquid in electrode modification. The other modifier was copper oxide nanoparticles/carbon nanofiber composite (CuO/CNF) provided by electrospinning and evaluated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR). Several electro-analytical parameters such as the electrochemical behavior of the modified electrode, scan rate, type and supporting electrolyte pH were studied for the determination of colchicine. Under the optimized experimental conditions, oxidative peak current increased linearly by increasing colchicine concentration in the range of 1.0 to 100.0 nM and detection limit was obtained 0.25 nM. The relative standard deviation for six replicate analyses of 20.0 nM and 58.0 nM colchicine solution was obtained to be ± 3.17% and ± 2.08%, respectively. The proposed electrochemical sensor was successfully applied for colchicine quantification in colchicine tablet and health human plasma with satisfying results. [ABSTRACT FROM AUTHOR]