Study of the histidine complex of uranium(IV): synthesis, spectrophotometric, magnetic and electrochemical properties

We synthesized the novel histidine complex of uranium(IV). A 1:3 mole ratio was found between metal and ligand by the mole ratio method, while –NH2 and –COO– groups of histidine behave as coordinating sites. The IR spectra confirmed the lone pair donating or coordinating sites. The elemental analysis confirmed the stoichiometry. The bathochromic shift with an increase in the optical density in the UV-Visible range indicated that the compound and its central metal ion hold uniform electronic charge distribution. The electrochemical results indicated a quasi-reversible (neither completely reversible nor completely irreversible) oxidation of the complex to its uranium(V) product at the platinum working electrode. The quasi-reversible process shows a comparatively slow electron transfer (ET) rate with the heterogeneous electron transfer rate constant ‘ks’ (3.4 ×  10–4 cm s-1) at 50 mV s-1 and 305 ± 0.5 K. The kinetics such as diffusion and charge transfer lead the reaction with an ECE (electrochemical–chemical–electrochemical) mechanism. The thermodynamic parameters of activation such as ΔH*; 4.257 kJ mol–1, ΔS*; -2.519 × 10–3 J mol–1 K–1 and ΔG* 4.26 kJ mol–1 helped to propose an associative mechanism of the electron transfer at the platinum working electrode.                     KEY WORDS: Uranium, Histidine, Spectroscopy, Electrochemistry, Kinetics   Bull. Chem. Soc. Ethiop. 2020, 34(3), 557-569.  DOI: https://dx.doi.org/10.4314/bcse.v34i3.1

Penentuan Persentase Uptake Radiofarmaka Tc99m Sulfur Colloid pada Sidik Hati (Liver Scan)

Based on data from the World Health Organization, showed that liver disease in Indonesia is in endemic high ranks. Early diagnosis of liver disease is very necessary for prevention and minimize the risk of liver disease. Research has been conducted on 28 patients on the biodistribution test of the liver scan using in vivo nuclear medicine technique that aims to determine the accumulation of counts Tc99m Sulfur Colloid in the body's metabolism, the percentage uptake activity in the heart, spleen, kidney, bladder, and liver as the target organ. The study was conducted using Tc99m obtained from elution of Mo99 generator and mixed with sulfur colloid. Tc99m allows a radiopharmaceutical can be detected and known location and sulfur colloid to determine where the target of radiopharmaceutical is accumulated. Liver scan is performed by injecting Tc99m Sulfur Colloid intravenously into the patient's arm as much as 2- 6mCi. Furthermore, the anterior posterior planar imaging in abdominal cavity at 5 minutes and 1 hour after injection of the patient by using a gamma camera. Determining the state of liver function can be seen from the percentage uptake activity at 5 minutes and 1 hour, the shape and size of the heart which can be evaluated from the image obtained. Biodistribution of Tc99m Sulfur Colloid showed a high percentage of the liver after 5 minutes and 1 hour. Based on the value percentage uptake activity obtained, there were 18 patients with a normal liver and 10 patients with abnormal liver