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Die isolering van Mo-99 uit klowingsmateriaal vir gebruik in 'n 99Mo/99mTc-generator

Synthesis of and potentiometric studies with bisphosphonate ligands APDDAM and PolyHEDP as potential carriers of radionuclides : in attempt to develop effective 117MSn radio pharmaceuticals for bone metastases

  • Authors: Ranqhai, Tsekiso
  • Date: 2014-08-18
  • Subjects: Radiochemistry , Bone metastasis - Radiotherapy , Phosphonates , Radioisotopes
  • Type: Thesis
  • Identifier: uj:12077 , http://hdl.handle.net/10210/11824
  • Description: M.Sc. (Chemistry) , Secondary cancer tumour formation, often called metastasis, remains one of the great scientific challenges in public health. Patients with skeletal metastases have a low survival rate, with great discomforts experienced by the sufferers. Pain, decreased mobility, pathologic bone fractures are some of the effects that these patients have to live with. Significant inroads have been made in using radio pharmaceuticals as a pain palliation treatment for bone metastases. They comprise of a bone seeking phosphonate ligand and a radionuclide. The structural variation of the phosphonate affects to a great extend the effectiveness of the radiopharmaceutical with the greatest shortfall being myelosuppression at high doses. In this study an attempt is made at synthesizing novel bisphosphonates, APDDAM and APDDPE. After several synthetic steps from the protected β-alanine tert butyl ester, the free acid precursor was achieved (as shown in the NMR and elemental analysis) in good yields. Unfortunately the final reaction step to form the bisphosphonate ligand was unsuccessful, with the free acid precursor dissociating in the acidic conditions to form salts. A polymer ligand poly-HEDP was synthesized from its free acid form in relatively low yields. The ligand was used in potentiometric studies with the metal ions Ca(II), Mg(II), Cu(II), Zn(II), Sn(II) and Sn(IV) to evaluate its potential as radiopharmaceutical candidate. The ESTA model formation constants obtained were used in the ECCLES blood plasma model to evaluate the competitive stability of the complexes against biological metal ions and ligands. The Sn(IV)-poly-HEDP complex was shown to be unstable, with a 100 % dissociation. On the other hand the Sn(II)-poly-HEDP showed much improved stability with 100 % of the metal ion remaining bound to the ligand.
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Die adsorpsie van natriumlinoleaat op verdunningsminerale in foskoriet en pirokseniet

Radiochemiese en ioonchromatografiese metodes vir die bepaling van silwerhaliedkomplekse en haliedione in sout- en oliematrikse

  • Authors: Taljaard, Immanda
  • Date: 2014-03-12
  • Subjects: Radiochemistry , Ion exchange chromatography , Chromatographic analysis , Silver halides , Halides
  • Type: Thesis
  • Identifier: uj:4311 , http://hdl.handle.net/10210/9663
  • Description: M.Sc. (Chemistry) , The storage as solid Ag12BI(s) of reactor produced 12BI (t~ = 1.6 x 107 a) in underground respositories can present an environmental problem due to the potential release of radioactive 12BI into the environment over extended storage periods. One process that causes concern is the solubilization of AgI through complexation when brought into contact with underground water, particularly those with high salt content. In this work the charaqterization of the complexation equilibria in the AgI(s)/I-(aq),CI-(aq) system was studied. Solu- I tions containing high CI- and low 1- concentrations were of special interest with regard to the possible formation of ternary complexes. The presence of AgICI22- was indicated experimentally but no evidence of other ternary species like AgI2CI2- or AgIsCIS- could be established. Solubilities were determined radiochemically by using specially prepared 110mAgI. Solubility curves for AgI in different I-/CI- mixtures were adequately explained in terms of models consisting of the species AgCls2-, AgC14S-, AgIs2-, AgI4s- and AgICI22-. Distribution curves were calculated for different I-/CI- mixtures. As an alternative detection mode for silver-determination a flow injection system incorporating a micro-column of activated alumina was used in conjuntion with flame atomic absorption spectrometry for the pre-concentration and determination of silver in water. The procedure was successfully applied to a range of water samples, but no determination of silver in halide or perchlorate media was possible. The limit of detection based on a sample volume of 15 cms was 4.5 ~gdm-3 and the relative standard deviations at 50 and 5 ~gdm-3 were 5.4 and 19%, respectively. In part B of this work a method for the determination of chloride in organic compounds (oils provided by the Atomic Energy Corporation) by using an Parr oxygen bomb and ion chromatography was studied. The combustion products were absorbed in H20. The solution was injected into an ion chromatograph equipped with an anion analytical column, membrane suppressor and conductivity detector. The instrument response was calibrated using different standard solutions. These were prepared from several organic solutions, an organic salt and from sodiumchloride. Calibration curves were linear over a wide range and presented good reproducibility. It differed however according to the type of standard solution used. The limit of detection was 255 ~gdm-3 and the relative standard deviations at 10, 1 and 0.5 ugcm-3 were 0.52, 1.64 and 3.5%, respectively. As an alternative decomposition method wet decomposition within a sealed system (autoclave) was used. Due to the high blank values in this method no analysis of substances could be made in the lower ugcm-3 range.
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