Evaluating the impact and potential of the chemical sciences in catalysing the economic development through potential chemical entrepreneurship in Lesotho

Science is central for research and innovation that are key drivers for economic development. However, with the never improving capital investment towards higher education in most African countries, the level of infrastructure in the universities hinders  adequate training of human resources and the economic development emanating from science and technology innovation. This paper shares the history, impact and the prospects of the chemical sciences program at the National University of Lesotho in transforming the local economy through translation of science with emphasis on potential commercialization and entrepreneurship in partnership with local entities: cooperatives, community-based organization or private smallmedium enterprises other than the few present and somewhat unwilling companies. Finally we recommend the coordination of the innovation and incubation initiatives in public sector to partner with the universities as centres of knowledge creation

Evaluating the influence of interactive simulations on learners’ academic performance in stoichiometry

Traditional teaching strategies dominate science classrooms in Lesotho, resulting in poor academic performance at each level. Information and  Communication Technology tools such as simulations offer potential benefits for improving science teaching. The purpose of this quasi-experimental  study was to evaluate the effect of simulations on learners’ performance and retention of stoichiometry concepts using Solomon’s four-group design.  Purposive sampling of two existing Form E (Grade 12) classes, with 81 learners, led to the creation of four groups. The study responds to the research  question: How does using simulations as part of an intervention affect learners’ academic performance in stoichiometry? Data were collected as learners’  scores for pre-tests and post-tests, designed to assess their understanding of stoichiometry, and analysed through ANOVA and t-tests. After the  intervention, the experimental group’s mean score (M = 44.2, σ = 18) was higher than that of control group (M = 32.6, σ = 15.8), and the difference  between the two mean scores was statistically significant, namely t(81) = 3.14, p = 0.002. The experimental group had a higher mean score for retention  in post-test (M = 47.4, σ =16.1) than the control group (M = 37.2, σ = 13.7) which was statistically significant, namely t(81) = 3.10, p = 0.003. Therefore, it  was concluded that simulations enhanced learners’ performance and could improve the retention of stoichiometry concepts. This study recommends  that simulations be used to supplement the teaching and learning of science, in particular chemistry.&nbsp

Development of a simple amino-modified silica-based colorimetric sensor for the detection of copper (II) ions in aqueous samples

Research projects form an important part of learning and preparing students for graduate training. While most cutting edge research requires highly sophisticated instruments, there is no such luxury in the Least Developed Countries, least of all, being accessible to undergraduate students. Consequently, undergraduate research projects require some level of improvisation and innovation to use easily available materials to carry out research, without compromising the quality of science. This paper reports the development of a simple amino-modified colorimetric sensor using silica gel modified with (3-aminopropyl)-triethoxysilane (APS) for the qualitative detection of Cu2+ ions in aqueous solutions in an effort to demonstrate the concept of ligand field strength and imbue interest in research in the undergraduate students. The sensor was immobilized on a glass stirring rod for simulated field applications. It responded considerably well at concentrations above 200 parts per million and neutral pH (7-8) giving response under 60 minutes of exposure with the increase in detection times as the concentration of the ions decreased. Modification of the APS with different substrates reduced its efficiency, demonstrating the necessity for primary amines. The binding of the Cu2+ ions seemed considerably stable for the sensor to be applied as a passive sampling device. This experiment has demonstrated that indeed, science does not only depend on sophisticated instrumentation but also simple ideas can generate interest in students while also achieving credible research results. It further demonstrates the importance of encouraging independent thinking to arouse interest as a way of improving the learning process

Hollow-Fibre-Supported Dispersive Liquid-Liquid Microextraction for Determination of Atrazine and Triclosan in Aqueous Samples

We report the application of the dispersive liquid-liquid microextraction coupled to hollow-fibre membrane-assisted liquid-phase microextraction and its application for extraction of atrazine and triclosan. Under optimum conditions, namely, 25 μL of a 1 : 4 chlorobenzene : ethyl acetate mixture dispersed in 1 mL of aqueous sample, 10% (m/v) NaCl, a magnetic stirrer speed at 600 rpm, and 10 minutes’ extraction time with toluene-filled fibre as the acceptor phase, the method demonstrates sufficient figures of merit. These include linearity (R2 ≥ 0.9975), intravial precision (%RSD ≤ 7.6), enrichment factors (127 and 142), limits of detection (0.0081 and 0.0169 µg/mL), and recovery from river water and sewerage (96–101%). The relatively high detection limits are attributed to the flame ionization detector which is less preferred than a mass spectrometer in trace analyses. This is the first report of a homogenous mixture of the dispersed organic solvent in aqueous solutions and its employment in extraction of organic compounds from aqueous solutions. It therefore adds yet another candidate in the pool of miniaturised solvent microextraction techniques

Bubbles in solvent microextraction : the influence of intentionally introduced bubbles on extraction efficiency

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Phytochemical characterization of the herbal concoctions made and sold in Lesotho that are claimed to treat COVID-19 and related respiratory ailments

Introduction Safety and efficacy of herbal products is a major health concern in countries with poor or no regulation regarding the ingredients, dosages, side effects, and contraindications of these traditional medicines. Herein we report the phytochemical characterization of the commercially available plant-derived concoctions in Lesotho, providing a possible scientific basis for the function and possible safety of such concoctions, based on the determined chemical compounds with the aid of documented phytochemical studies on medicinal plants. Purpose The purpose of this study was to use the documented phytochemical studies of medicinal plants in Lesotho and other parts of the world as a basis to study and characterize the commercially available traditional and herbal remedies that are claimed to fight respiratory ailments including those related to COVID-19 infection in Lesotho – Southern Africa. Methods Phytochemical screening was carried out on three herbal concoctions produced and sold in Lesotho using simple wet chemistry procedures. Solvent microextraction was carried out followed by gas chromatography and mass spectrometry for the purpose of qualitative analysis of the volatile organic compounds (VOCs). Results At least 5 major phytochemicals in each concoction were obtained with tannins and flavonoids quantified spectrophotometrically. One concoction (ROCK) had a total tannin content of about 75 µg/mL and a total flavonoid content of 300 µg/mL relative to the other plants averaging 20 and 50 µg/mL respectively. GC-MS analyses of the concoctions revealed the varying degrees of presence of VOCs with one showing hardly any peaks on the chromatogram indicating that either the concoction was not made from plants, or the VOCs had almost completely been lost during the processes of preparation. The other compounds detected, namely, benzoic acid (48% in ROCK), phthalic acid ester (detected in all concoctions), and glycerine, are consequent on processing indicating the importance of processing in the safety of processed plants as some of these are hazardous beyond certain thresholds. Conclusions The tested products show variable amounts of phytochemicals with ROCK showing more volatiles than the other two products. The detected phytochemicals indicate that the products are indeed plant derived while the VOCs profile indicates difference in treatment. The detection of phthalates suggests the importance of testing these products for the presence of unwanted chemicals

Efficacy of Cellulose Degrading Microbial Strains on the Decomposition of Sewage Water Microalgae for the Production of Biogas

Sewage water microalgae are potential sources of feed stock for the production of biofuel. In this study, six treatment combinations of microbial strains (C, N1 and N2) in single and combined treatments were used in a 5L plastic container as anaerobic digester. The use of sewage water microalgae alone was used as a negative control; and a separate application of effective microorganisms (EM) were used for comparison. A volume of 3L sewage water suspension containing 300g of microalgae biomass were used in all plastic containers as a feedstock. All treatment applications including the control showed some activity of pressure development in each bag per treatment per cycle except the combined treatment of strain (C, N1, N2). Significant volume of biogas production (4-5L/300g)) and pressure development (517.80 and 544.35 Nm-2 was observed in the first cycle when using cellulose degrading microorganism (C) alone and the combined treatment with nitrogen fixing strain (N1), respectively

Development of a coupled dispersive liquid-liquid micro-extraction with supported liquid phase micro-extraction for triclosan determination in wastewater

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 efficiency 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). The 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 confidence 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

Bioprospecting of Essential Oil-Bearing Plants: Rapid Screening of Volatile Organic Compounds Using Headspace Bubble-in-Drop Single-Drop Microextraction for Gas Chromatography Analysis

Essential oils are vital constituents of oil-bearing plants. However, their screening still demands harvesting of the plant for laboratory analysis. We report herein a simple, rapid and robust headspace bubble-in-drop microextraction screening technique (BID-SPME) requiring only small amounts of plant material. The optimised method uses 0.5 g of the crushed plant leaves sample obtained in a 2 mL capped chromatography vial, heated to 55 °C and sampled with 2 µL heptadecane in a Hamilton gastight syringe equilibrated for 15 min exposed to the headspace volume. The method was applied to three plants, Pinus radiata, Tagetes minuta and Artemisia afra, which are known for their essential oil content. The method was able to extract at least 80% of the oil constituents in such abundance that they could be easily annotated using the gas chromatography–mass spectrometry (GC–MS) mass spectral libraries. The major volatile organic compounds (VOCs) detected included tagetone, terpinen-4-ol, ocimenone, caryophyllene, dihydrotagetone, terpinolene and artemisia ketone, just to mention a few, at different concentrations in different plants. Importantly, these annotated VOCs were also reported in other studies in the same and even different plants, extracted using normal steam distillation and importantly those reported in the literature for different extraction techniques