http://repository.tml.nul.ls:80/handle/123456789/187 2006-01-03T20:07:23Z http://repository.tml.nul.ls:80/handle/123456789/1419 Highlighting mass spectrometric fragmentation diffrences and similarities between hydroxycinnamoyl-quinic acids and hydroxycinnamoyl-isocitric acids Masike, Keabetswe; Mhlongo, Msizi I.; Mudau, Shonisani P.; Nobela, Ofentse; Ncube, Efficient N.; Tugizimana, Fidele; George, Mosotho J.; Madala, Ntakadzeni E. Plants contain a myriad of metabolites which exhibit diverse biological activities. However, in-depth analyses of these natural products with current analytical platforms remains an undisputed challenge due to the multidimensional chemo-diversity of these molecules, amplifid by both isomerization and conjugation. In this study, we looked at molecules such as hydroxyl-cinnamic acids (HCAs), which are known to exist as positional and geometrical isomers conjugated to diffrent organic acids namely quinic- and isocitric acid. 2017-01-01T00:00:00Z http://repository.tml.nul.ls:80/handle/123456789/1418 Development of a coupled dispersive liquid-liquid micro-extraction with supported liquid phase micro-extraction for triclosan determination in wastewater Letseka, Thabiso; George, Mosotho As attention is drawn towards the monitoring of the so-called emerging pollutants, some common household chemicals are not well researched. Household antimicrobials can also present wastewater treatment challenges if not taken cognisance of. Herein we report the application of a recently reported coupled dispersive liquid-liquid micro-extraction (DLLME) with supported liquid phase micro-extraction (LPME) for the extraction of triclosan from wastewater. A univariate approach was used to investigate various parameters amenable to DLLME while no attempt was made to optimise the LPME, achieving the following optimum conditions: 25 µL of a 1:1 toluene-chloroform mixture with 10% sodium chloride into 1 mL aqueous triclosan solutions and extraction time of 15 min achieving an enrichment effiency 167 times the reference solution prepared with distilled water, good linearity (R2 = 0.9946) with the estimated limit of detection at 0.013 µg/mL and good repeatability (%RSD ≤ 10). Th method showed considerable ruggedness with a similar linearity (R2 = 0.9957) and repeatability (%RSD < 10), with only the limit of detection being compromised (0.31 µg/mL) when applied to a wastewater sample using a matrix-matched standard addition approach. Although the GC-FID method detected triclosan in the wastewater sample, the results were negated by those from the GC-MS; as such it therefore could not be concluded with confience whether the water contained any triclosan or not. However, the results demonstrated the potential of this method in determination of triclosan in water-based samples when the extraction was coupled to a more rugged system such as a GC-MS. 2017-02-08T00:00:00Z http://repository.tml.nul.ls:80/handle/123456789/1148 Synthesis and characterization of Y3+-doped TiO2 nanocomposites for photocatalytic applications Macheli, Lebohang; Narayan, Himanshu; Alemu, Hailemichael; Gundu Rao, T. K.; Thakurdesai, Madhavi The TiO2·[Y2O3]x (x = 0.1–0.4) nanocomposites (NCs) with an average particle size of 74 nm were prepared by the method of chemical co-precipitation followed by hydrolysis (CPH). Their visible light photocatalytic activity was investigated for the degradation of congo red (CR) dye. All NCs showed improved degradation as compared to the polycrystalline samples of similar compositions prepared by the solid-state reaction (SSR) route (average particle size of a few micrometers), as well as to the pure TiO2. The better photocatalytic activity of the NCs was attributed to their smaller particle size. Another comparison of the results with those obtained with Zn2+/Fe3+ ions co-doped TiO2 NCs, under similar experimental conditions, revealed that in the Y3+-doped NCs, particle size might not be the only factor responsible for the improved photocatalytic properties. It was concluded that the Y3+ ion-mediated suppression of the unwanted e−/h+ recombination could be the possible factor leading to additional enhancement. 2009-01-01T00:00:00Z http://repository.tml.nul.ls:80/handle/123456789/147 Factors affecting nurse-patient communication in the maternity unit at Motebang district Hospital, Lesotho Qhola, P. J.; George, M.; Mokhosi, B. et al. Article could not be found 2014-01-01T00:00:00Z