The work has been focused on the preconcentration techniques for determination of uranium on the modified sorbent, with the final use of ICP-OES and ICP-MS. First ICP-OES at a wavelength of 385.958 nm was used for determination of uranium. Parameters were optimized and the effect of mineral acids (HCl, HNO3), tensides (Septonex, Ajatin) and organic reagents like (4-(2-pyridylazo)resorcinol, ammonium pyrrolidinedithiocarbamate, 8-hydroxyquinoline-5-sulphonic acid and 1,2-dihydroxyanthraquinone-3-sulphonic acid) was observed. For ICP-MS an isotope 238U was chosen. As an internal standard 209Bi (200 ?g•l-1) was used. Modified silica gel was used (Silicagel tethered with C18, C8 alkyls and phenyl) and two types of Amberlite XAD 4 and XAD 16 for the preconcentration of uranium (VI). Commercially produced Amberlite was modified as follows: Drying at 100 °C (24 hours), milled, minced sorbent was selected and fractionated to particles size ranging from 0.32 to 0.63 ?m and finally activated in methanol. The deionised water and Septonex (5•10-3 mol•l-1) at pH 8 were used for Amberlite conditioning. The optimal sorption of uranium (VI) proceeded at pH 8 in the presence of 4-(2-pyridylazo)resorcinol or ammonium pyrrolidinedithiocarbamate with Amberlite XAD-16 moreover with 1,2-dihydroxyanthraquinone-3-sulphonic acid. All organic reagents have mass concentration five time larger than uranium . For the elution of uranium the mixture of 1 mol•l-1 HNO3 with acetone (ratio of 1:1) was used. Acetone was evaporated and the final analysis performed using ICP-OES. The preconcentration of uranium (VI) using Silicagel-C18 conditioning was performed with ethanol, deionised water and Zephyraminu (5•10-4 mol•l-1) at pH 8. For the Silica-C8 and Silicagel-Phenyl the same conditioning procedure without zephyramin was used. Silica-C18 had the highest sorption efficiency with 1,2-dihydroxyanthraquinone-3-sulphonic acid, Silicagel-C8 with ammonium pyrrolidinedithiocarbamate and Silicagel-Phenyl with 8-hydroxyquinoline-5-sulfonic acid, all organic reagents have mass concentration five time larger than uranium concentration. As an optimal elution mixture acetone and ethanol (ratio of 1:1) in the presence of 1 mol•l-1 HCl was evaluated. Acetone and ethanol was evaporated and the final analysis was performed using ICP-MS. Silicagel-C18 was evaluate as the most effective in the presence of zephyramin and 1,2-dihydroxyanthraquinone-3-sulphonic acid. Sorption was also tested in the presence of 20 ?g•l-1 microelements (Be, V, Co, Ni, Y, Pb, Th, Cd) and in the presence of a defined concentrations of K, Na, Ca, Mg, Al and Fe. Direct analysis of uranium was carried out on samples of water from the river Ploucnice and Turonian aquifers containing uranium, 3,5 and 19,3 ?g•l-1. Different type of water required preconcentration of uranium (VI) on Silica-C18 in the presence of 1,2-dihydroxyanthraquinone-3-sulphonic acid and zephyramin. The analysis results gave statistically satisfactory results, which were confirmed using standard addition of 20 ?g•l-1.

Physikalische und chemische Charakterisierung von Lithiumionenzellen

Physikalische und chemische Charakterisierung von Lithiumionenzellen

Boron element plays an important role for our country since approximately 70% of the world&rsquo / s reserves are in Turkey. It is widely used in different areas of industry. Besides being vital for the plants, it is important also for human health. It has been shown that high boron exposure does not affect fertility negatively and also with an increasing boron exposure, risk of prostate and cervical cancers decreases. There are different opinions regarding health effects of boron. There are both positive and negative findings. Therefore, determination of boron in body fluids such as urine and blood is necessary to monitor exposed concentration level and its relation with diseases. Furthermore, these studies may contribute to define a reference value for safe maximum daily boron intake. In this study, a method previously developed by our research group was applied for the determination of boron in urine samples. Urine and blood samples were collected from human subjects living or working in different regions of Balikesir where boron reserves are located. While urine analysis was done by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), due to lower concentrations of boron in blood, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for blood analysis. A sensitive method was developed using ICP-MS. Samples were digested in microwave oven by applying optimized digestion procedures. Indium (In) and Beryllium (Be) internal standards were spiked into the urine and blood samples, respectively. A sample introduction system containing no glass or silica surfaces was used in ICP-MS to eliminate boron memory effect. Two isotopes of the boron, 10B and 11B, were monitored during the study. Space charge effect due to Na+ ion and carbon interference on B and Be signals was investigated in detail. Limit of Detection was 0.021 mg/L for ICP-OES and it was 2.2 &micro / g/L for ICP-MS. The accuracies of the methods were checked by using NIST 1573a Tomato Leaves and BCR Human Hair certified reference materials for urine and blood, respectively.