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.
- Full Text:
- 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.
- Full Text:
Profiling of organic extractives in wood and dissolving pulping process by chromatographic and spectroscopic methods
- Authors: Kilulya, Kessy Fidel
- Date: 2012-11-05
- Subjects: Lipophilic wood extractives , Wood-pulp analysis , Chromatographic analysis , Spectrum analysis
- Type: Thesis
- Identifier: uj:7337 , http://hdl.handle.net/10210/8086
- Description: Ph.D. , The main objective of this study was to investigate the presence, variations and the fate of lipophilic extractives during all the stages in the dissolving pulp production process. Lipophilic wood extractives which include fatty acids, sterols, hydrocarbons, steroid hydrocarbons and ketones are organic compounds present in the wood and dissolving pulp which are soluble in organic solvents. Their presence in wood and pulp has negative effects on both the pulping process and the quality of the produced dissolving pulp. Comparison of two Eucalyptus species (E. grandis and E. dunnii) at three different sites (Richmond, Umvoti and Ixopo in KwaZulu-Natal Province, South Africa) revealed that lipophilic extractives were higher in E. dunnii than in E. grandis in all the sampled sites and that the woods at the Ixopo site were found to have the highest amount of lipophilic extractives. The quantitative variation of lipophilic extractives in wood was found to be significantly affected by respective sites and tree species. The principal component analysis (PCA) model, which was used to correlate soil parameters and amount of lipophilic extractives in woods per each site, revealed that high amounts of lipophilic extractives were found in trees grown at sites with a high composition of clay soil and organic matter. Thus if the industry is to avoid the high levels of lipophilic extractives in wood, sandy sites should be the choice to grow the trees. Partial least squares (PLS) modelling revealed that sterols and saturated fatty acids significantly influence the quality parameters (Kappa number, viscosity, copper number, cellulose yield and retained carbohydrates) of dissolving pulp, whereas unsaturated fatty acids and unsaturated sterols in particular were found to positively correlate with the Kappa number, thus affecting its measurement.The main objective of this study was to investigate the presence, variations and the fate of lipophilic extractives during all the stages in the dissolving pulp production process. Lipophilic wood extractives which include fatty acids, sterols, hydrocarbons, steroid hydrocarbons and ketones are organic compounds present in the wood and dissolving pulp which are soluble in organic solvents. Their presence in wood and pulp has negative effects on both the pulping process and the quality of the produced dissolving pulp. Comparison of two Eucalyptus species (E. grandis and E. dunnii) at three different sites (Richmond, Umvoti and Ixopo in KwaZulu-Natal Province, South Africa) revealed that lipophilic extractives were higher in E. dunnii than in E. grandis in all the sampled sites and that the woods at the Ixopo site were found to have the highest amount of lipophilic extractives. The quantitative variation of lipophilic extractives in wood was found to be significantly affected by respective sites and tree species. The principal component analysis (PCA) model, which was used to correlate soil parameters and amount of lipophilic extractives in woods per each site, revealed that high amounts of lipophilic extractives were found in trees grown at sites with a high composition of clay soil and organic matter. Thus if the industry is to avoid the high levels of lipophilic extractives in wood, sandy sites should be the choice to grow the trees. Partial least squares (PLS) modelling revealed that sterols and saturated fatty acids significantly influence the quality parameters (Kappa number, viscosity, copper number, cellulose yield and retained carbohydrates) of dissolving pulp, whereas unsaturated fatty acids and unsaturated sterols in particular were found to positively correlate with the Kappa number, thus affecting its measurement. Viscosity of pulp which is an important quality parameter was also found to be positively influenced by sterol residues, whereas the reducing properties of pulp were found to be affected by sterols and saturated fatty acids with a carbon chain length of less than C20.
- Full Text:
- Authors: Kilulya, Kessy Fidel
- Date: 2012-11-05
- Subjects: Lipophilic wood extractives , Wood-pulp analysis , Chromatographic analysis , Spectrum analysis
- Type: Thesis
- Identifier: uj:7337 , http://hdl.handle.net/10210/8086
- Description: Ph.D. , The main objective of this study was to investigate the presence, variations and the fate of lipophilic extractives during all the stages in the dissolving pulp production process. Lipophilic wood extractives which include fatty acids, sterols, hydrocarbons, steroid hydrocarbons and ketones are organic compounds present in the wood and dissolving pulp which are soluble in organic solvents. Their presence in wood and pulp has negative effects on both the pulping process and the quality of the produced dissolving pulp. Comparison of two Eucalyptus species (E. grandis and E. dunnii) at three different sites (Richmond, Umvoti and Ixopo in KwaZulu-Natal Province, South Africa) revealed that lipophilic extractives were higher in E. dunnii than in E. grandis in all the sampled sites and that the woods at the Ixopo site were found to have the highest amount of lipophilic extractives. The quantitative variation of lipophilic extractives in wood was found to be significantly affected by respective sites and tree species. The principal component analysis (PCA) model, which was used to correlate soil parameters and amount of lipophilic extractives in woods per each site, revealed that high amounts of lipophilic extractives were found in trees grown at sites with a high composition of clay soil and organic matter. Thus if the industry is to avoid the high levels of lipophilic extractives in wood, sandy sites should be the choice to grow the trees. Partial least squares (PLS) modelling revealed that sterols and saturated fatty acids significantly influence the quality parameters (Kappa number, viscosity, copper number, cellulose yield and retained carbohydrates) of dissolving pulp, whereas unsaturated fatty acids and unsaturated sterols in particular were found to positively correlate with the Kappa number, thus affecting its measurement.The main objective of this study was to investigate the presence, variations and the fate of lipophilic extractives during all the stages in the dissolving pulp production process. Lipophilic wood extractives which include fatty acids, sterols, hydrocarbons, steroid hydrocarbons and ketones are organic compounds present in the wood and dissolving pulp which are soluble in organic solvents. Their presence in wood and pulp has negative effects on both the pulping process and the quality of the produced dissolving pulp. Comparison of two Eucalyptus species (E. grandis and E. dunnii) at three different sites (Richmond, Umvoti and Ixopo in KwaZulu-Natal Province, South Africa) revealed that lipophilic extractives were higher in E. dunnii than in E. grandis in all the sampled sites and that the woods at the Ixopo site were found to have the highest amount of lipophilic extractives. The quantitative variation of lipophilic extractives in wood was found to be significantly affected by respective sites and tree species. The principal component analysis (PCA) model, which was used to correlate soil parameters and amount of lipophilic extractives in woods per each site, revealed that high amounts of lipophilic extractives were found in trees grown at sites with a high composition of clay soil and organic matter. Thus if the industry is to avoid the high levels of lipophilic extractives in wood, sandy sites should be the choice to grow the trees. Partial least squares (PLS) modelling revealed that sterols and saturated fatty acids significantly influence the quality parameters (Kappa number, viscosity, copper number, cellulose yield and retained carbohydrates) of dissolving pulp, whereas unsaturated fatty acids and unsaturated sterols in particular were found to positively correlate with the Kappa number, thus affecting its measurement. Viscosity of pulp which is an important quality parameter was also found to be positively influenced by sterol residues, whereas the reducing properties of pulp were found to be affected by sterols and saturated fatty acids with a carbon chain length of less than C20.
- Full Text:
Advances in the single-drop micro-extraction pre-concentration technique
- Authors: George, Joseph Mosotho
- Date: 2008-08-15T07:56:19Z
- Subjects: Extraction (Chemistry) , Chromatographic analysis , Pesticides
- Type: Thesis
- Identifier: uj:7909 , http://hdl.handle.net/10210/879
- Description: Pesticide residue analysis is very important both in agriculture and environmental protection. The effectiveness of the analytical method depends very much on the extraction and preconcentration of the analytes prior to the actual analysis, as these analytes occur in trace concentrations that may be lower than the detection limit of the instrument. Various methods of extraction and pre-concentration have been introduced in an effort to decrease costs and other negative environmental impacts without compromising efficiency. One such method is single-drop micro-extraction (SDME), whose benefits cannot be overemphasised. This method has been recently introduced in the pool of pre-concentration methods for pesticide and other organic residues. In this study, the SDME method has been developed using chloroform as a solvent for preconcentration of a ten-component mixture of triazine (TP619) herbicides, followed by analysis by gas chromatography and flame ionisation detector (ppm level detection) and mass spectrometry for detection at sub-ppb level. The developed method uses the simple introduction of an air bubble to the micro-litre droplet of the organic solvent used for extraction of the triazines. This air-bubble showed the increase in the extraction efficiency of the method by about 30% relative to the optimised extraction without the air bubble. The air bubble works very well with addition of the salt (10% NaCl) to the solution being extracted, with further extraction enhancements being observed. Traditionally, the solution being extracted is stirred to achieve good mass transfer. However, the present method does not require stirring as stirring makes the system unstable resulting in reduced precision. The optimum conditions for the newly developed method, named bubble-in-drop single-drop micro-extraction (BID-SDME) were found to be as follows: 1 μL chloroform, 0.5 μL air bubble, 10% NaCl and static equilibration for 20 minutes, while the sample volume is 1 mL. This method showed linearity in the region of 1 ppm to 0.05 ppb (about six orders of magnitude) as long as the instrumental settings were optimised for increased sensitivity. The RSD values observed in this method were better than those recorded in literature, being <10%. Some instrumental manipulations are necessary to realise the full potential of the instrument. Various settings were explored on the GC-MS to optimise its performance below the ppb level. It was observed that the configuration that gave the best sensitivity and the lowest limits of detection was the high-pressure and split-less injection mode. This improved the detection limits of the instrument by 2 orders of magnitude (from 1 ppb to below 0.05 ppb). The GC-MS performance was further improved by the use of selected ion monitoring (SIM) mode of analysis. This technique reduced the interferences from the co-extracted compounds that can compromise the precision and accuracy of the analytical method especially at low concentration applicable in trace analysis. The new BID-SDME method was applied to various samples (dam water, synthetic hard water, dam sediment, humic and sandy soil samples) giving unsurpassed efficiencies with very low RSD values. In these systems, NaCl addition (10% w/v) not only increased extraction efficiency but also had a matrix-normalising effect as the RSD values were reduced and the matrix effects somewhat diminished. The application of this method to orange juice required the addition of only 5% NaCl (not 10% like the other samples). The results obtained with the extraction of orange juice were better than those recorded in literature. The normalising effect was further observed as the RSD values with addition of the NaCl were reduced the RSD from 11.7 (salt-free solution) to 5.56 (5% NaCl). These application experiments were carried out at the 0.2 ppb level using spiked samples. The method was compared against the other extraction techniques used in trace analysis (especially SPME) and it performed better overall giving lower RSD values and much improved detection limits. The calculated detection limits for the ten triazines used in the mixture were in the region of parts per trillion (0.9-14 ppt) with RSD values of < 10% with the use of internal standard. , Prof. D.B.G. Williams Mr. R. Meyer
- Full Text:
- Authors: George, Joseph Mosotho
- Date: 2008-08-15T07:56:19Z
- Subjects: Extraction (Chemistry) , Chromatographic analysis , Pesticides
- Type: Thesis
- Identifier: uj:7909 , http://hdl.handle.net/10210/879
- Description: Pesticide residue analysis is very important both in agriculture and environmental protection. The effectiveness of the analytical method depends very much on the extraction and preconcentration of the analytes prior to the actual analysis, as these analytes occur in trace concentrations that may be lower than the detection limit of the instrument. Various methods of extraction and pre-concentration have been introduced in an effort to decrease costs and other negative environmental impacts without compromising efficiency. One such method is single-drop micro-extraction (SDME), whose benefits cannot be overemphasised. This method has been recently introduced in the pool of pre-concentration methods for pesticide and other organic residues. In this study, the SDME method has been developed using chloroform as a solvent for preconcentration of a ten-component mixture of triazine (TP619) herbicides, followed by analysis by gas chromatography and flame ionisation detector (ppm level detection) and mass spectrometry for detection at sub-ppb level. The developed method uses the simple introduction of an air bubble to the micro-litre droplet of the organic solvent used for extraction of the triazines. This air-bubble showed the increase in the extraction efficiency of the method by about 30% relative to the optimised extraction without the air bubble. The air bubble works very well with addition of the salt (10% NaCl) to the solution being extracted, with further extraction enhancements being observed. Traditionally, the solution being extracted is stirred to achieve good mass transfer. However, the present method does not require stirring as stirring makes the system unstable resulting in reduced precision. The optimum conditions for the newly developed method, named bubble-in-drop single-drop micro-extraction (BID-SDME) were found to be as follows: 1 μL chloroform, 0.5 μL air bubble, 10% NaCl and static equilibration for 20 minutes, while the sample volume is 1 mL. This method showed linearity in the region of 1 ppm to 0.05 ppb (about six orders of magnitude) as long as the instrumental settings were optimised for increased sensitivity. The RSD values observed in this method were better than those recorded in literature, being <10%. Some instrumental manipulations are necessary to realise the full potential of the instrument. Various settings were explored on the GC-MS to optimise its performance below the ppb level. It was observed that the configuration that gave the best sensitivity and the lowest limits of detection was the high-pressure and split-less injection mode. This improved the detection limits of the instrument by 2 orders of magnitude (from 1 ppb to below 0.05 ppb). The GC-MS performance was further improved by the use of selected ion monitoring (SIM) mode of analysis. This technique reduced the interferences from the co-extracted compounds that can compromise the precision and accuracy of the analytical method especially at low concentration applicable in trace analysis. The new BID-SDME method was applied to various samples (dam water, synthetic hard water, dam sediment, humic and sandy soil samples) giving unsurpassed efficiencies with very low RSD values. In these systems, NaCl addition (10% w/v) not only increased extraction efficiency but also had a matrix-normalising effect as the RSD values were reduced and the matrix effects somewhat diminished. The application of this method to orange juice required the addition of only 5% NaCl (not 10% like the other samples). The results obtained with the extraction of orange juice were better than those recorded in literature. The normalising effect was further observed as the RSD values with addition of the NaCl were reduced the RSD from 11.7 (salt-free solution) to 5.56 (5% NaCl). These application experiments were carried out at the 0.2 ppb level using spiked samples. The method was compared against the other extraction techniques used in trace analysis (especially SPME) and it performed better overall giving lower RSD values and much improved detection limits. The calculated detection limits for the ten triazines used in the mixture were in the region of parts per trillion (0.9-14 ppt) with RSD values of < 10% with the use of internal standard. , Prof. D.B.G. Williams Mr. R. Meyer
- Full Text:
Experimental and modelling studies on the interactions of metals and natural organic matter in cooling water at coal powergeneration plants
- Authors: Bosire, Geoffrey Orina
- Date: 2015
- Subjects: Eskom (Firm) , Chromatographic analysis , Photooxidative stress , Coal-fired power plants , Industrial water supply
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/225032 , uj:22719
- Description: Abstract: Eskom, the chief power generating and supply company in South Africa, has power stations that are mainly coal-fired. The surface water used in the condenser tubes for cooling purposes at these stations is rich in dissolved organic and inorganic compounds. Due to the relatively high concentration of alkaline earth metals (notably Ca and Mg) in the water, super-saturation of mineral phases that are responsible for scale formation occurs in a range of physico-chemical parameters (such as pH, ionic strength and temperature). Natural organic matter (NOM) in aquatic environments influences the speciation and mobility of metals, and is available in high concentrations in different fractions. The humic substances fraction, for instance, has concentrations ranging 10-200 mg/L. Studies in this thesis typify the characteristics and role of NOM with respect to complexation to metal cations. This complexation is understood to minimize scaling potential at the Lethabo and Kriel power stations, as archetypical power generating stations in South Africa. Furthermore, PHREEQC based simulations using the modified Tipping and Hurley database with Windermere’s Humic Acid Model (T_H-WHAM) were used to speciate and quantify complexation outputs. Conventional NOM characterization techniques such as ultra-violet (UV) analysis, total and dissolved organic carbon (TOC/DOC) analysis, specific ultra violet absorbance (SUVA) measurements have been found lacking in terms of analysis time and robustness. As an alternative, detailed characterization of NOM compounds in raw and cooling water (extracted by solid phase extraction) was achieved by the use of liquid chromatography-organic carbon detection-organic nitrogen (LC-OCD-OND), fluorescence excitation emission matrices (FEEM) and 2 dimensional gas x gas chromatography with a time-of-flight mass spectrometer (GC x GC-TOFMS). Organic compounds with different molecular weights were characterized i.e. those with >600 g by LC-OCD-OND and <600 g by GC x GC-TOFMS). Fluorescing/chromophoric NOM compounds determined by FEEM were mainly humic substances. The fractions obtained by GC x GC-TOFMS (such as aliphatic and aromatic), highly depended on pre... , Ph.D. (Chemistry)
- Full Text:
- Authors: Bosire, Geoffrey Orina
- Date: 2015
- Subjects: Eskom (Firm) , Chromatographic analysis , Photooxidative stress , Coal-fired power plants , Industrial water supply
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/225032 , uj:22719
- Description: Abstract: Eskom, the chief power generating and supply company in South Africa, has power stations that are mainly coal-fired. The surface water used in the condenser tubes for cooling purposes at these stations is rich in dissolved organic and inorganic compounds. Due to the relatively high concentration of alkaline earth metals (notably Ca and Mg) in the water, super-saturation of mineral phases that are responsible for scale formation occurs in a range of physico-chemical parameters (such as pH, ionic strength and temperature). Natural organic matter (NOM) in aquatic environments influences the speciation and mobility of metals, and is available in high concentrations in different fractions. The humic substances fraction, for instance, has concentrations ranging 10-200 mg/L. Studies in this thesis typify the characteristics and role of NOM with respect to complexation to metal cations. This complexation is understood to minimize scaling potential at the Lethabo and Kriel power stations, as archetypical power generating stations in South Africa. Furthermore, PHREEQC based simulations using the modified Tipping and Hurley database with Windermere’s Humic Acid Model (T_H-WHAM) were used to speciate and quantify complexation outputs. Conventional NOM characterization techniques such as ultra-violet (UV) analysis, total and dissolved organic carbon (TOC/DOC) analysis, specific ultra violet absorbance (SUVA) measurements have been found lacking in terms of analysis time and robustness. As an alternative, detailed characterization of NOM compounds in raw and cooling water (extracted by solid phase extraction) was achieved by the use of liquid chromatography-organic carbon detection-organic nitrogen (LC-OCD-OND), fluorescence excitation emission matrices (FEEM) and 2 dimensional gas x gas chromatography with a time-of-flight mass spectrometer (GC x GC-TOFMS). Organic compounds with different molecular weights were characterized i.e. those with >600 g by LC-OCD-OND and <600 g by GC x GC-TOFMS). Fluorescing/chromophoric NOM compounds determined by FEEM were mainly humic substances. The fractions obtained by GC x GC-TOFMS (such as aliphatic and aromatic), highly depended on pre... , Ph.D. (Chemistry)
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Isolation, characterisation and biological activity of some compounds from rapanea melanophloeos (L.) Mez.
- Authors: Lukhele, Thabile
- Date: 2012-08-20
- Subjects: Myrsinaceae , Materia medica, Vegetable , Medicinal plants , Chromatographic analysis , Bioactive compounds
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/377234 , uj:2815 , http://hdl.handle.net/10210/6252
- Description: M.Sc. , The continued use and popularity of plant based traditional medicine necessitates scientific validation of the therapeutic potential of medicinal plants through phytochemical and pharmacological screening as well as the isolation and identification of bioactive compounds. Since the pharmacological effectiveness of medicinal plants is affected by several intrinsic and extrinsic factors, studies on the variations on chemical composition and biological activity are important as well. These provide a scientific rationale for using plants from different regions for the same medicinal purposes and allow traditional healers and consumers to make informed decisions with regard to the collection and use. Rapanea melanophloeos is a popular medicinal plant from the Myrsinaceae family widely distributed in southern Africa. It‟s bark, fruits and rarely the leaves are used traditionally for ailments ranging from stomach disorders, respiratory problems to disorders of the nervous system. Available chemical information reports on the accumulation of benzoquinones as major compounds, as well as some triterpenoid saponins and tannins. In view of the plant‟s wide distribution and medicinal use of different plant parts, this study comparatively evaluated the chemical composition of various crude extracts of the leaves, fruits and bark of plants collected from six localities. This was coupled with antibacterial tests to evaluate the therapeutic potential of different solvent extracts of the leaves, fruits and bark as well as the isolation of bioactive compounds from the fruits. Plants were collected from six different localities between Swaziland and South Africa and sequentially extracted with petroleum ether, ethyl acetate, methanol and water as a series of increasingly polar solvents. Thin layer chromatography (TLC), Gas-Chromatography/Mass spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC) were used to obtain a semi-quantitative chemical composition profile of different extracts. The TLC fingerprints of petroleum ether, ethyl acetate and methanol extracts showed the accumulation of non-polar terpenes, benzoquinones, saponins, tannins and flavonoids in the three plant parts. Slight variations in the chemical composition of the leaves, bark, and fruits were noted. Some components occurred in specific plant parts and others occurred in all three plants. The chemical profile of the leaves and bark were quite comparable in most instances with the fruits showing a generally different profile. This confirms previous literature reports on the comparability of leaves and the bark accounting for interchangeable use in traditional medicine.
- Full Text:
- Authors: Lukhele, Thabile
- Date: 2012-08-20
- Subjects: Myrsinaceae , Materia medica, Vegetable , Medicinal plants , Chromatographic analysis , Bioactive compounds
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/377234 , uj:2815 , http://hdl.handle.net/10210/6252
- Description: M.Sc. , The continued use and popularity of plant based traditional medicine necessitates scientific validation of the therapeutic potential of medicinal plants through phytochemical and pharmacological screening as well as the isolation and identification of bioactive compounds. Since the pharmacological effectiveness of medicinal plants is affected by several intrinsic and extrinsic factors, studies on the variations on chemical composition and biological activity are important as well. These provide a scientific rationale for using plants from different regions for the same medicinal purposes and allow traditional healers and consumers to make informed decisions with regard to the collection and use. Rapanea melanophloeos is a popular medicinal plant from the Myrsinaceae family widely distributed in southern Africa. It‟s bark, fruits and rarely the leaves are used traditionally for ailments ranging from stomach disorders, respiratory problems to disorders of the nervous system. Available chemical information reports on the accumulation of benzoquinones as major compounds, as well as some triterpenoid saponins and tannins. In view of the plant‟s wide distribution and medicinal use of different plant parts, this study comparatively evaluated the chemical composition of various crude extracts of the leaves, fruits and bark of plants collected from six localities. This was coupled with antibacterial tests to evaluate the therapeutic potential of different solvent extracts of the leaves, fruits and bark as well as the isolation of bioactive compounds from the fruits. Plants were collected from six different localities between Swaziland and South Africa and sequentially extracted with petroleum ether, ethyl acetate, methanol and water as a series of increasingly polar solvents. Thin layer chromatography (TLC), Gas-Chromatography/Mass spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC) were used to obtain a semi-quantitative chemical composition profile of different extracts. The TLC fingerprints of petroleum ether, ethyl acetate and methanol extracts showed the accumulation of non-polar terpenes, benzoquinones, saponins, tannins and flavonoids in the three plant parts. Slight variations in the chemical composition of the leaves, bark, and fruits were noted. Some components occurred in specific plant parts and others occurred in all three plants. The chemical profile of the leaves and bark were quite comparable in most instances with the fruits showing a generally different profile. This confirms previous literature reports on the comparability of leaves and the bark accounting for interchangeable use in traditional medicine.
- Full Text:
Iodine mediated preparation of beta-acetoxysulfides and stereoselective synthesis of (E)-1,3-diphenyl-1-butene dimers
- Authors: Marakalala, Mokgethwa B.
- Date: 2018
- Subjects: Sulfur compounds , Catalysis , Chromatographic analysis , Stereochemistry
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279618 , uj:30031
- Description: Abstract: -Hydroxysulfides comprise a significant segment of sulfur-containing natural products. Owing to their biological importance, their presence in a number of natural products in addition to their use as key intermediates in the synthesis of pharmaceuticals and substrates for the preparation of allylic alcohols, benzoxathiepines, benzodiazepines, thioketones, -substituted unsaturated enones, and -hydroxysulfoxides [15b], a number of methodologies have been reported for the synthesis of β-hydroxysulfides. Regioselective epoxide ring opening and 1,2-difunctionalization of alkenes are the commonly employed routes in the synthesis of such compounds. However, most of the reported methods suffer from one or more limitations including the use of transition metals, poor regioselectivity, long reaction times, limited substrate scope, the need for expensive and toxic reagents as well as the need for the preparation of an epoxide precursor and the formation of undesirable side products via rearrangement of epoxides and the oxidation of thiols, especially in the thiolysis of epoxides. In addressing some of these issues, we herein report in the current study a transition metal-free iodine catalysed preparation of acetate masked -hydroxysulfides (-acetoxysulfides) in the presence of a disulfide and a diacetoxyiodobenzene. The scope and limitations of the methodology are investigated in detail. In demonstrating the importance of (-acetoxysulfides) in organic synthesis, the methodology was fine tuned to provide styrene dimers that incorporate a sulfur heteroatom via a head-to-tail dimerization. The importance of sulfur in the synthesis of advanced materials, the scarcity of methodologies for the incorporation of sulfur to styrene monomers, as well as the attractiveness of the head-to-tail dimerization which generates an allylic chiral centre that is reported to be present in a number of biologically important organic molecules, makes the current method attractive in organic synthesis and thus, the results from the investigation of the scope and limitations of the reaction are reported along with full experimental details. , M.Sc. (Chemistry)
- Full Text:
- Authors: Marakalala, Mokgethwa B.
- Date: 2018
- Subjects: Sulfur compounds , Catalysis , Chromatographic analysis , Stereochemistry
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279618 , uj:30031
- Description: Abstract: -Hydroxysulfides comprise a significant segment of sulfur-containing natural products. Owing to their biological importance, their presence in a number of natural products in addition to their use as key intermediates in the synthesis of pharmaceuticals and substrates for the preparation of allylic alcohols, benzoxathiepines, benzodiazepines, thioketones, -substituted unsaturated enones, and -hydroxysulfoxides [15b], a number of methodologies have been reported for the synthesis of β-hydroxysulfides. Regioselective epoxide ring opening and 1,2-difunctionalization of alkenes are the commonly employed routes in the synthesis of such compounds. However, most of the reported methods suffer from one or more limitations including the use of transition metals, poor regioselectivity, long reaction times, limited substrate scope, the need for expensive and toxic reagents as well as the need for the preparation of an epoxide precursor and the formation of undesirable side products via rearrangement of epoxides and the oxidation of thiols, especially in the thiolysis of epoxides. In addressing some of these issues, we herein report in the current study a transition metal-free iodine catalysed preparation of acetate masked -hydroxysulfides (-acetoxysulfides) in the presence of a disulfide and a diacetoxyiodobenzene. The scope and limitations of the methodology are investigated in detail. In demonstrating the importance of (-acetoxysulfides) in organic synthesis, the methodology was fine tuned to provide styrene dimers that incorporate a sulfur heteroatom via a head-to-tail dimerization. The importance of sulfur in the synthesis of advanced materials, the scarcity of methodologies for the incorporation of sulfur to styrene monomers, as well as the attractiveness of the head-to-tail dimerization which generates an allylic chiral centre that is reported to be present in a number of biologically important organic molecules, makes the current method attractive in organic synthesis and thus, the results from the investigation of the scope and limitations of the reaction are reported along with full experimental details. , M.Sc. (Chemistry)
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The quality of selected local and international homoeopathic mother tinctures according to thin layer chromatographic (tlc) analysis
- Authors: Scheepmaker, Mande
- Date: 2011-06-30T06:50:30Z
- Subjects: Homeopathic pharmacy , Tinctures (Pharmacy) testing , Chromatographic analysis
- Type: Thesis
- Identifier: uj:7153 , http://hdl.handle.net/10210/3757
- Description: M.Tech. , Homoeopathic mother tinctures have an extensive therapeutic history and as the emphasis of health is becoming a worldwide trend, homoeopathic preparations are becoming increasingly popular. However, the quality control and quality assurance still remains a challenge because of the high variability of chemical components involved (Pande and Pathak, 2006). Homoeopathic mother tinctures, singularly and in combinations, contain a copious number of compounds in complex matrices in which no single active constituent is responsible for the overall efficacy. This creates a challenge in establishing quality control standards for raw materials and standardization of finished herbal drugs, resulting in varying standards for these preparations globally (Chitlange, 2008). Various homoeopathic mother tinctures were selected for comparative analysis and consisted of: Artemisia absinthium, Rosmarinus officinalis e foliis recentibus, Sambucus nigra and Salvia officinalis are all manufactured according to the German Homoeopathic Pharmacopoeia method 3a, indicating the use of fresh plant material to produce the mother tincture (German Homoeopathic Pharmacopoeia, 2003). Many factors influence the quality of homoeopathic mother tinctures and many parameters must be met when assessing the quality of these products (Bandaranayake, 2006). Through thin layer chromatography analysis of the selected homoeopathic mother tinctures one is able to determine whether the active components of the samples are present and deduce whether the sample complies with the minimum standard quality stipulated in the German Homoeopathic Pharmacopoeia as well as the Good Manufacturing Practice (Waksmundzka-Hojnos et al., 2008). Samples of each homoeopathic mother tincture, purchased from both local and international manufacturers, were decanted into amber glass bottles, randomized and relabeled. The colour of each sample was assessed and compared to the standard colour stated in the German Homoeopathic Pharmacopoeia. For the thin layer chromatographic analysis, each sample together with reference sample were prepared and developed on both aluminum backed TLC plates and glass backed HPTLC plates. Photographs of the resultant chromatograms were taken, the presence of the active components were identified and the quality of each homoeopathic mother tincture was deduced.
- Full Text:
- Authors: Scheepmaker, Mande
- Date: 2011-06-30T06:50:30Z
- Subjects: Homeopathic pharmacy , Tinctures (Pharmacy) testing , Chromatographic analysis
- Type: Thesis
- Identifier: uj:7153 , http://hdl.handle.net/10210/3757
- Description: M.Tech. , Homoeopathic mother tinctures have an extensive therapeutic history and as the emphasis of health is becoming a worldwide trend, homoeopathic preparations are becoming increasingly popular. However, the quality control and quality assurance still remains a challenge because of the high variability of chemical components involved (Pande and Pathak, 2006). Homoeopathic mother tinctures, singularly and in combinations, contain a copious number of compounds in complex matrices in which no single active constituent is responsible for the overall efficacy. This creates a challenge in establishing quality control standards for raw materials and standardization of finished herbal drugs, resulting in varying standards for these preparations globally (Chitlange, 2008). Various homoeopathic mother tinctures were selected for comparative analysis and consisted of: Artemisia absinthium, Rosmarinus officinalis e foliis recentibus, Sambucus nigra and Salvia officinalis are all manufactured according to the German Homoeopathic Pharmacopoeia method 3a, indicating the use of fresh plant material to produce the mother tincture (German Homoeopathic Pharmacopoeia, 2003). Many factors influence the quality of homoeopathic mother tinctures and many parameters must be met when assessing the quality of these products (Bandaranayake, 2006). Through thin layer chromatography analysis of the selected homoeopathic mother tinctures one is able to determine whether the active components of the samples are present and deduce whether the sample complies with the minimum standard quality stipulated in the German Homoeopathic Pharmacopoeia as well as the Good Manufacturing Practice (Waksmundzka-Hojnos et al., 2008). Samples of each homoeopathic mother tincture, purchased from both local and international manufacturers, were decanted into amber glass bottles, randomized and relabeled. The colour of each sample was assessed and compared to the standard colour stated in the German Homoeopathic Pharmacopoeia. For the thin layer chromatographic analysis, each sample together with reference sample were prepared and developed on both aluminum backed TLC plates and glass backed HPTLC plates. Photographs of the resultant chromatograms were taken, the presence of the active components were identified and the quality of each homoeopathic mother tincture was deduced.
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Chromium speciation analysis by ion chromatography coupled with ICP-OES
- Authors: Jansen van Vuuren, Samantha
- Date: 2012-09-04
- Subjects: Speciation (Chemistry) , Chromium , Ion exchange chromatography , Chromatographic analysis , Inductively coupled plasma spectrometry
- Type: Thesis
- Identifier: uj:3510 , http://hdl.handle.net/10210/6899
- Description: M.Sc. , The behaviour i.e. the distribution, bioavailability and toxicity of an element depends on the particular species in which it is present. That being said the prediction of the behaviour of species can therefore not be predicted by determination of the total concentration alone. Speciation analysis is thus an important process, which seeks to identify and quantify the species that occur in a sample. By identifying the species one is better equipped to predict the behaviour of the element if it were released into the ecosystem as well as if it were used in industrial processes. The speciation analysis of the dominant chromium species, Cr(III) and Cr(VI), has received much attention as these contradictory species are involved in many industrial processes such as plating and tanning for example. The species have opposing behaviour as Cr(III) is found to be a necessary micronutrient for mammals where as Cr(VI) is known to be toxic. Of the numerous methods developed for chromium speciation analysis, the on-line process of chromatographic preconcentration followed by simultaneous detection with a sensitive detector produces a synergistic effect for the successful speciation analysis of chromium. It was thus decided to study ion chromatography hyphenated with an ICP-OES as a means of studying chromium species. Anion chromatography coupled with ICP-OES was the basis for the development of the first method. Complexation of Cr(III) with EDTA to form a monovalent anion preceded its separation from Cr(VI) as the chromate anion. A carbonate-bicarbonate eluent was used to elute the species from a Dionex AG 9 guard column coupled with an AS 9 separation column. This method proved to be effective and fast, with each analysis taking less than two minutes. The second method was based on cation chromatography in the form of a Dionex CG12A guard column being coupled with an ICP-OES spectrometer as the detector. This method made use of a gradient elution program in which hexavalent chromium was eluted first with ammonium nitrate followed by trivalent chromium with nitric acid. This method was successfully applied to synthetic samples and was found to be effective.
- Full Text:
- Authors: Jansen van Vuuren, Samantha
- Date: 2012-09-04
- Subjects: Speciation (Chemistry) , Chromium , Ion exchange chromatography , Chromatographic analysis , Inductively coupled plasma spectrometry
- Type: Thesis
- Identifier: uj:3510 , http://hdl.handle.net/10210/6899
- Description: M.Sc. , The behaviour i.e. the distribution, bioavailability and toxicity of an element depends on the particular species in which it is present. That being said the prediction of the behaviour of species can therefore not be predicted by determination of the total concentration alone. Speciation analysis is thus an important process, which seeks to identify and quantify the species that occur in a sample. By identifying the species one is better equipped to predict the behaviour of the element if it were released into the ecosystem as well as if it were used in industrial processes. The speciation analysis of the dominant chromium species, Cr(III) and Cr(VI), has received much attention as these contradictory species are involved in many industrial processes such as plating and tanning for example. The species have opposing behaviour as Cr(III) is found to be a necessary micronutrient for mammals where as Cr(VI) is known to be toxic. Of the numerous methods developed for chromium speciation analysis, the on-line process of chromatographic preconcentration followed by simultaneous detection with a sensitive detector produces a synergistic effect for the successful speciation analysis of chromium. It was thus decided to study ion chromatography hyphenated with an ICP-OES as a means of studying chromium species. Anion chromatography coupled with ICP-OES was the basis for the development of the first method. Complexation of Cr(III) with EDTA to form a monovalent anion preceded its separation from Cr(VI) as the chromate anion. A carbonate-bicarbonate eluent was used to elute the species from a Dionex AG 9 guard column coupled with an AS 9 separation column. This method proved to be effective and fast, with each analysis taking less than two minutes. The second method was based on cation chromatography in the form of a Dionex CG12A guard column being coupled with an ICP-OES spectrometer as the detector. This method made use of a gradient elution program in which hexavalent chromium was eluted first with ammonium nitrate followed by trivalent chromium with nitric acid. This method was successfully applied to synthetic samples and was found to be effective.
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Polymer nanocomposites-based sensors for the detection of lung cancer volatile organic biomarkers
- Authors: Mgwenya, Tintswalo N.
- Date: 2018
- Subjects: Catalysis , Chromatographic analysis , Stereochemistry
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279521 , uj:30019
- Description: M.Sc. (Nanoscience) , Abstract: Cancer has been and is still of great interest and a disease that draws researcher’s attention. Exhaled breath biomarkers are a promising solution for early detection of lung cancer on its early developmental stages. The analysis of specific Volatile Organic Compounds (VOCs) in exhaled breath give insight of metabolic and physiological activities of an individual. Application of nanoscience using metals oxides and polymer nanocomposites through gas sensing is an interesting research path that brings cost-effectiveness and fast results using the non-invasive route for the detection of biomarkers. This mode of detection was employed for the detection of lung cancer exhaled breath biomarkers. This study aimed at developing polymer-metal-oxide-nanocomposites based sensors of high sensitivity and tuneable selectivity towards specific targeted lung cancer VOC biomarkers to improve the detection methods for lung cancer VOCs. Materials such as Manganese dioxide, Titanium dioxide and Tin dioxide, carbon nanoparticles and polymer nanocomposite based Volatile Organic Compounds sensors were utilized. Synthesized materials were characterized using BET, SEM, XRD and Raman spectroscopy. Sensors were fabricated by solution mixing method of metal-oxide, carbon nanoparticles and a biopolymer to produce a nanocomposite. The prepared nanocomposites were drop-casted onto electrodes and dried under room temperature. Prepared sensors were tested on VOCs 2-Hexanal, Hexanal and Dodecane. Overall, our result suggested the sensors were responsible for lung cancer VOCs.
- Full Text:
- Authors: Mgwenya, Tintswalo N.
- Date: 2018
- Subjects: Catalysis , Chromatographic analysis , Stereochemistry
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279521 , uj:30019
- Description: M.Sc. (Nanoscience) , Abstract: Cancer has been and is still of great interest and a disease that draws researcher’s attention. Exhaled breath biomarkers are a promising solution for early detection of lung cancer on its early developmental stages. The analysis of specific Volatile Organic Compounds (VOCs) in exhaled breath give insight of metabolic and physiological activities of an individual. Application of nanoscience using metals oxides and polymer nanocomposites through gas sensing is an interesting research path that brings cost-effectiveness and fast results using the non-invasive route for the detection of biomarkers. This mode of detection was employed for the detection of lung cancer exhaled breath biomarkers. This study aimed at developing polymer-metal-oxide-nanocomposites based sensors of high sensitivity and tuneable selectivity towards specific targeted lung cancer VOC biomarkers to improve the detection methods for lung cancer VOCs. Materials such as Manganese dioxide, Titanium dioxide and Tin dioxide, carbon nanoparticles and polymer nanocomposite based Volatile Organic Compounds sensors were utilized. Synthesized materials were characterized using BET, SEM, XRD and Raman spectroscopy. Sensors were fabricated by solution mixing method of metal-oxide, carbon nanoparticles and a biopolymer to produce a nanocomposite. The prepared nanocomposites were drop-casted onto electrodes and dried under room temperature. Prepared sensors were tested on VOCs 2-Hexanal, Hexanal and Dodecane. Overall, our result suggested the sensors were responsible for lung cancer VOCs.
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Production of mycotoxin standards with 99% chromatographic purity
- Authors: Ngulla, Horace Masalo
- Date: 2019
- Subjects: Food - Microbiology , Mycotoxins , Chromatographic analysis , Food - Safety measures - Standards - South Africa
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/417710 , uj:35386
- Description: Abstract: Mycotoxins are secondary metabolites produced by a substantial number of fungal species that are harmful and pose a major threat to food safety and security globally. The increasing need for better food safety management and effective food safety testing services with priority leverage on mycotoxin regulation in agricultural commodities and by-products at both domestic and international levels requires accurate quantification that demands the use of high purity mycotoxin standards as reference materials. Mycotoxin standards are very limited in South Africa and if available, the purity is not certain, and the prices are extremely way too expensive thereby limiting food safety management. There are no studies reporting on the production of mycotoxins as reference materials in South Africa despite that the Council of Scientific and Industrial Research (CSIR) has been producing a few for commercialization.. , M.Sc. (Biotechnology)
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- Authors: Ngulla, Horace Masalo
- Date: 2019
- Subjects: Food - Microbiology , Mycotoxins , Chromatographic analysis , Food - Safety measures - Standards - South Africa
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/417710 , uj:35386
- Description: Abstract: Mycotoxins are secondary metabolites produced by a substantial number of fungal species that are harmful and pose a major threat to food safety and security globally. The increasing need for better food safety management and effective food safety testing services with priority leverage on mycotoxin regulation in agricultural commodities and by-products at both domestic and international levels requires accurate quantification that demands the use of high purity mycotoxin standards as reference materials. Mycotoxin standards are very limited in South Africa and if available, the purity is not certain, and the prices are extremely way too expensive thereby limiting food safety management. There are no studies reporting on the production of mycotoxins as reference materials in South Africa despite that the Council of Scientific and Industrial Research (CSIR) has been producing a few for commercialization.. , M.Sc. (Biotechnology)
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Analysis and speciation of arsenic in staple food products in South Africa by ion chromatography coupled to high resolution inductively coupled plasma-mass spectrometry
- Authors: Thosago, Magadima
- Date: 2019
- Subjects: Food - Toxicology - South Africa , Arsenic - Bioaccumulation - South Africa , Chromatographic analysis , Plasma spectroscopy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/418904 , uj:35536
- Description: Abstract: Arsenic (As) is a metalloid that is found ubiquitously in the environment and poses a potential threat to human, animal and plant health due to the high toxicity of its inorganic forms, arsenite As(III) and arsenate As(V). It is introduced into soils and groundwater by anthropogenic activities such as the previous or current use of Asbased pesticides in farming areas and commercially as a by-product of metal smelting operations. Exposure to arsenic can occur through different pathways such as the direct ingestion of As-containing water or through As-transfer via the crop-soil-water system. Arsenic is absorbed by plants through their root system thus gaining access to the food chain and then the body. Chronic, long term exposure to low levels of arsenic is associated with an increased risk of cancer. .. , M.Sc. (Chemistry)
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- Authors: Thosago, Magadima
- Date: 2019
- Subjects: Food - Toxicology - South Africa , Arsenic - Bioaccumulation - South Africa , Chromatographic analysis , Plasma spectroscopy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/418904 , uj:35536
- Description: Abstract: Arsenic (As) is a metalloid that is found ubiquitously in the environment and poses a potential threat to human, animal and plant health due to the high toxicity of its inorganic forms, arsenite As(III) and arsenate As(V). It is introduced into soils and groundwater by anthropogenic activities such as the previous or current use of Asbased pesticides in farming areas and commercially as a by-product of metal smelting operations. Exposure to arsenic can occur through different pathways such as the direct ingestion of As-containing water or through As-transfer via the crop-soil-water system. Arsenic is absorbed by plants through their root system thus gaining access to the food chain and then the body. Chronic, long term exposure to low levels of arsenic is associated with an increased risk of cancer. .. , M.Sc. (Chemistry)
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Solid phase-based micro-extraction methods for pre-concentration and removal of neutral and basic drugs from environmental matrices before chromatographic determination
- Authors: Mpayipheli, Neliswa
- Date: 2020
- Subjects: Solid-phase synthesis , Chromatographic analysis , Extraction (Chemistry)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/474132 , uj:42726
- Description: Abstract: Pharmaceuticals are considered as emerging contaminants, mainly because they are frequently detected in the environment. They are constantly used for human health reasons and are necessary for remedy, so it is almost impossible to restrict their use. The continuous detection of pharmaceuticals in environment water confirms that methods of water treatment plants were not made specifically for removal of these contaminants. These compounds are composed of natural and synthetic compounds, which make them to be very diverse. As a result of growing demand for medical treatment, the production of pharmaceuticals is constantly increasing. Therefore, there is a need for development of new efficient methods for the extraction, pre-concentration and removal of these analytes from different environment matrices. Therefore, the aim of this study was to prepare cheap and efficient materials as adsorbents for extraction and preconcentration of acetaminophen (ACT), caffeine (CAF) and carbamazepine (CBZ) from various environmental matrices... , M.Sc. (Chemistry)
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- Authors: Mpayipheli, Neliswa
- Date: 2020
- Subjects: Solid-phase synthesis , Chromatographic analysis , Extraction (Chemistry)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/474132 , uj:42726
- Description: Abstract: Pharmaceuticals are considered as emerging contaminants, mainly because they are frequently detected in the environment. They are constantly used for human health reasons and are necessary for remedy, so it is almost impossible to restrict their use. The continuous detection of pharmaceuticals in environment water confirms that methods of water treatment plants were not made specifically for removal of these contaminants. These compounds are composed of natural and synthetic compounds, which make them to be very diverse. As a result of growing demand for medical treatment, the production of pharmaceuticals is constantly increasing. Therefore, there is a need for development of new efficient methods for the extraction, pre-concentration and removal of these analytes from different environment matrices. Therefore, the aim of this study was to prepare cheap and efficient materials as adsorbents for extraction and preconcentration of acetaminophen (ACT), caffeine (CAF) and carbamazepine (CBZ) from various environmental matrices... , M.Sc. (Chemistry)
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