Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a01
Abdellah Muhammed, A. Hussen, T. Kaneta
A simple, fast, low-cost and sensitive microfluidic paper-based analytical device (u-PADs) integrated with the co-precipitation enrichment procedure was developed to analyse Ni(II) in tap and mineral water samples. The impacting factors, including pH, centrifugation (5 min at 4000 rpm), and amounts of reagents were optimized. The limit of detection of 0.009 mg L-1 and linear range of 0.03-2.00 mg L-1 were achieved with good intra- and inter-day precision (4.7 and 5.6% RSD, respectively). The recovery tests were conducted by spiking tap and mineral water samples and analyzed using the u-PADs after co-precipitation enrichment. The results obtained by the proposed method were validated by inductively coupled plasma-optical emission spectrometry (ICP-OES). The recoveries of the present method and ICP-OES were ranged from 92.4-106.8% and 92.9-97.2%, respectively. The two sets of (u-PADs and ICP-OES) results were in good agreement, as a paired t-test indicated no significant differences. The proposed method could be utilized for analyzing trace levels of Ni(II) in water samples in developing countries where the availability of conventional analytical instruments are significant problems.
{"title":"Trace nickel analysis in water samples via paper-based devices coupled with co-precipitation","authors":"Abdellah Muhammed, A. Hussen, T. Kaneta","doi":"10.17159/0379-4350/2023/v77a01","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a01","url":null,"abstract":"A simple, fast, low-cost and sensitive microfluidic paper-based analytical device (u-PADs) integrated with the co-precipitation enrichment procedure was developed to analyse Ni(II) in tap and mineral water samples. The impacting factors, including pH, centrifugation (5 min at 4000 rpm), and amounts of reagents were optimized. The limit of detection of 0.009 mg L-1 and linear range of 0.03-2.00 mg L-1 were achieved with good intra- and inter-day precision (4.7 and 5.6% RSD, respectively). The recovery tests were conducted by spiking tap and mineral water samples and analyzed using the u-PADs after co-precipitation enrichment. The results obtained by the proposed method were validated by inductively coupled plasma-optical emission spectrometry (ICP-OES). The recoveries of the present method and ICP-OES were ranged from 92.4-106.8% and 92.9-97.2%, respectively. The two sets of (u-PADs and ICP-OES) results were in good agreement, as a paired t-test indicated no significant differences. The proposed method could be utilized for analyzing trace levels of Ni(II) in water samples in developing countries where the availability of conventional analytical instruments are significant problems.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a08
A. Adeleke, S. Islam, K. Olofinsan, V. Salau, B. Omondi
The synthesis of three pyridinyl imines (L1-L3) with electron-donating and electron-withdrawing functional groups, as well as their silver(I) complexes (1a-3a, 1b-3b and 1c-3c), resulted from our ongoing search for novel metallodrugs with potential pharmacological activity. Various analytical and spectroscopic analyses were used to characterize the Ag(I) complexes. The single crystal X-ray diffraction analysis of complexes 3a and 3b in the solid state confirmed their linear geometry around the Ag(I) center. In vitro antibacterial properties of the complexes evaluated using the minimum inhibitory concentration (MIC) method revealed that complexes containing either a Me- or an F-substituent exhibited greater activity. The ferric-reducing antioxidant power (FRAP) experiment revealed that complexes with hydroxyl substituents have high antioxidant potential. These complexes with IC50 values ranging from 0.86 to 2.47 mg mL-1 outperformed ascorbic acid, with an IC50 of 2.68 mg mL-1. The reported complexes bound to CT-DNA via intercalation mode with significant binding constants for complexes whose ligands bore the OH- substituent. Bovine serum albumin (BSA) binding affinity to the complexes ranges from moderate to high. The studied complexes with methyl substituents are promising anti-cervical cancer candidates.
{"title":"Mononuclear discrete Ag(I) complexes of aryl substituted (E)-N-phenyl-1-(pyridin-3-yl)methanimine: In vitro biological activities and interactions with biomolecules","authors":"A. Adeleke, S. Islam, K. Olofinsan, V. Salau, B. Omondi","doi":"10.17159/0379-4350/2023/v77a08","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a08","url":null,"abstract":"The synthesis of three pyridinyl imines (L1-L3) with electron-donating and electron-withdrawing functional groups, as well as their silver(I) complexes (1a-3a, 1b-3b and 1c-3c), resulted from our ongoing search for novel metallodrugs with potential pharmacological activity. Various analytical and spectroscopic analyses were used to characterize the Ag(I) complexes. The single crystal X-ray diffraction analysis of complexes 3a and 3b in the solid state confirmed their linear geometry around the Ag(I) center. In vitro antibacterial properties of the complexes evaluated using the minimum inhibitory concentration (MIC) method revealed that complexes containing either a Me- or an F-substituent exhibited greater activity. The ferric-reducing antioxidant power (FRAP) experiment revealed that complexes with hydroxyl substituents have high antioxidant potential. These complexes with IC50 values ranging from 0.86 to 2.47 mg mL-1 outperformed ascorbic acid, with an IC50 of 2.68 mg mL-1. The reported complexes bound to CT-DNA via intercalation mode with significant binding constants for complexes whose ligands bore the OH- substituent. Bovine serum albumin (BSA) binding affinity to the complexes ranges from moderate to high. The studied complexes with methyl substituents are promising anti-cervical cancer candidates.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a06
Kwakhanya Mkwakwi, E. Hosten, R. Betz, A. Abrahams, Tatenda Madanhire
Five novel complexes were prepared by reacting 2-((E)-(tert-butylimino)methyl)phenol (HL2) with Ln(NO3)3xH2O (Ln = Gd and Dy ; x = 6 and 5, respectively) and LnCl3-6H2O (Ln = Nd, Gd and Dy). The crystal structures of the former two Ln(III) nitrate complexes are isostructural and the coordination sphere is composed of three monodentate HL2 ligands bonded to the metal centre through the phenolic oxygen atom and three nitrate ions coordinated in a bidentate fashion. Both complexes are nine-coordinate and SHAPE analysis reveals that they adopted a muffin polyhedra geometric type. The average Ln-Onitrate and Ln-Ophenolate bond lengths are 2.5059 and 2.2816 A, respectively. The complexes derived from the chloride salts exhibited an octahedral geometry with four monodentate Schiff base ligands [Ln-Ophenolate distances range from 2.229(4) to 2.2797(18) A] coordinating in the equatorial positions and two chloride ions [average Ln-Cl bond length is 2.6530 A, and average Cl-Ln-Cl angles is 180o] in axial positions. The ligand coordinated through the phenolate oxygen with the phenolic proton migrating to the imino nitrogen to give a zwitterionic form of the ligand. There are weak C-H-Cl interactions present and O-H-N hydrogen bonds are also observed in the crystal packing.
{"title":"The coordination behaviour of 2-((E)-(ferf-butylimino)methyl) phenol towards lanthanide nitrate and chloride salts","authors":"Kwakhanya Mkwakwi, E. Hosten, R. Betz, A. Abrahams, Tatenda Madanhire","doi":"10.17159/0379-4350/2023/v77a06","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a06","url":null,"abstract":"Five novel complexes were prepared by reacting 2-((E)-(tert-butylimino)methyl)phenol (HL2) with Ln(NO3)3xH2O (Ln = Gd and Dy ; x = 6 and 5, respectively) and LnCl3-6H2O (Ln = Nd, Gd and Dy). The crystal structures of the former two Ln(III) nitrate complexes are isostructural and the coordination sphere is composed of three monodentate HL2 ligands bonded to the metal centre through the phenolic oxygen atom and three nitrate ions coordinated in a bidentate fashion. Both complexes are nine-coordinate and SHAPE analysis reveals that they adopted a muffin polyhedra geometric type. The average Ln-Onitrate and Ln-Ophenolate bond lengths are 2.5059 and 2.2816 A, respectively. The complexes derived from the chloride salts exhibited an octahedral geometry with four monodentate Schiff base ligands [Ln-Ophenolate distances range from 2.229(4) to 2.2797(18) A] coordinating in the equatorial positions and two chloride ions [average Ln-Cl bond length is 2.6530 A, and average Cl-Ln-Cl angles is 180o] in axial positions. The ligand coordinated through the phenolate oxygen with the phenolic proton migrating to the imino nitrogen to give a zwitterionic form of the ligand. There are weak C-H-Cl interactions present and O-H-N hydrogen bonds are also observed in the crystal packing.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a03
M. Saadati
The present study proposes a simple and inexpensive photometric method for the selective determination of Ag(I). This method employed a home-made double beam photometer for the determination of silver ions based on an optode sensor prepared by immobilization of 5-(P-Dimethylaminobenzylidene)-rhodanine (PDR) on triacetyl cellulose (TAC) membrane. Two green LEDs as sources of light and light-dependent resistors (LDRs) as detectors were used in the proposed device. The LEDs are turned on by a programmable microcontroller that receives signals from light passed through the sensor, and the absorbance is calculated and displayed on a Liquid-crystal display (LCD) screen. With the optimum conditions, the calibration plot was linear in the concentration range of 0.5-6 μg mL-1. For five replicate determinations of 2 μg mL-1 Ag(I) and the related detection limits, the relative standard deviations were 2.29% and 0.25 μg mL-1, respectively. The method was applied successfully for determining silver in a silver sulphadiazine cream, a radiology effluent, and radiology film samples and the results obtained were in good agreement with those of the standard flame atomic absorption spectroscopy (FAAS) method.
{"title":"A simple method for colourimetric determination of silver using a home-made double beam photometer","authors":"M. Saadati","doi":"10.17159/0379-4350/2023/v77a03","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a03","url":null,"abstract":"The present study proposes a simple and inexpensive photometric method for the selective determination of Ag(I). This method employed a home-made double beam photometer for the determination of silver ions based on an optode sensor prepared by immobilization of 5-(P-Dimethylaminobenzylidene)-rhodanine (PDR) on triacetyl cellulose (TAC) membrane. Two green LEDs as sources of light and light-dependent resistors (LDRs) as detectors were used in the proposed device. The LEDs are turned on by a programmable microcontroller that receives signals from light passed through the sensor, and the absorbance is calculated and displayed on a Liquid-crystal display (LCD) screen. With the optimum conditions, the calibration plot was linear in the concentration range of 0.5-6 μg mL-1. For five replicate determinations of 2 μg mL-1 Ag(I) and the related detection limits, the relative standard deviations were 2.29% and 0.25 μg mL-1, respectively. The method was applied successfully for determining silver in a silver sulphadiazine cream, a radiology effluent, and radiology film samples and the results obtained were in good agreement with those of the standard flame atomic absorption spectroscopy (FAAS) method.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a10
J. Sewry, A. Ngqinambi, K. Ngcoza
The South African grade 9 Natural Sciences curriculum suggests the use of everyday science to introduce the usefulness and the relatability of science to learners. Many learners, however, seem to have a negative attitude towards science learning and science as an entity. This study is an intervention that sought to ascertain the attitudes of grade 8 and 9 learners in under-resourced schools in South Africa after they had carried out kitchen chemistry hands-on practical activities at science clubs in under-resourced township schools. The learners were interviewed about their experiences, and university student volunteers at the science clubs were also interviewed. An inductive-deductive thematic approach was used to analyse the qualitative interview data. The findings of the study revealed that the learners had a more positive attitude toward science after they had been engaged in the kitchen chemistry hands-on practical activities. Additionally, the integration of everyday knowledge promoted conceptual understanding and improved the performance of the learners. The interviews with the student volunteers revealed aspects that they thought would improve learners' attitudes to science. Science clubs run by university student volunteers could assist in promoting a positive attitude to science among learners.
{"title":"Attitudes to science when doing kitchen chemistry at science clubs","authors":"J. Sewry, A. Ngqinambi, K. Ngcoza","doi":"10.17159/0379-4350/2023/v77a10","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a10","url":null,"abstract":"The South African grade 9 Natural Sciences curriculum suggests the use of everyday science to introduce the usefulness and the relatability of science to learners. Many learners, however, seem to have a negative attitude towards science learning and science as an entity. This study is an intervention that sought to ascertain the attitudes of grade 8 and 9 learners in under-resourced schools in South Africa after they had carried out kitchen chemistry hands-on practical activities at science clubs in under-resourced township schools. The learners were interviewed about their experiences, and university student volunteers at the science clubs were also interviewed. An inductive-deductive thematic approach was used to analyse the qualitative interview data. The findings of the study revealed that the learners had a more positive attitude toward science after they had been engaged in the kitchen chemistry hands-on practical activities. Additionally, the integration of everyday knowledge promoted conceptual understanding and improved the performance of the learners. The interviews with the student volunteers revealed aspects that they thought would improve learners' attitudes to science. Science clubs run by university student volunteers could assist in promoting a positive attitude to science among learners.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a11
L. Madikizela
Apart from the studies which reported the occurrence of steroid hormones and antibiotics in wastewater treatment plants (WWTPs) back in 2004, 2007 and 2012, the evidence for monitoring of pharmaceuticals in South African water bodies intensified from 2014. Therefore, this study reviewed the analytical methods developed and applied in South Africa for the purpose of monitoring pharmaceuticals and their metabolites in water. At the same time, pharmaceuticals and their metabolites detected in South African waters are reviewed. To date, there is over 100 pharmaceuticals detected in South African waters with most studies focussing on quantitative analysis of non-steroidal anti-inflammatory drugs (NSAID), antibiotics, antiretroviral drugs and carbamazepine. Various sources of pharmaceuticals in the environment are reported, with WWTPs found as the major contributor to their occurrence in South African rivers. Notably, a NSAID, ibuprofen, with concentrations found exceeding 100 μg L-1 in selected WWTPs has also been found at high levels reaching 60 μg L-1 in river water. Mostly, pharmaceuticals detected in wastewater are also reported in corresponding rivers. The present review details pharmaceuticals that should be included in environmental monitoring studies performed in South Africa, while also identifying areas for future research through the research gap analysis.
{"title":"A journey of 10 years in analytical method development and environmental monitoring of pharmaceuticals in South African waters","authors":"L. Madikizela","doi":"10.17159/0379-4350/2023/v77a11","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a11","url":null,"abstract":"Apart from the studies which reported the occurrence of steroid hormones and antibiotics in wastewater treatment plants (WWTPs) back in 2004, 2007 and 2012, the evidence for monitoring of pharmaceuticals in South African water bodies intensified from 2014. Therefore, this study reviewed the analytical methods developed and applied in South Africa for the purpose of monitoring pharmaceuticals and their metabolites in water. At the same time, pharmaceuticals and their metabolites detected in South African waters are reviewed. To date, there is over 100 pharmaceuticals detected in South African waters with most studies focussing on quantitative analysis of non-steroidal anti-inflammatory drugs (NSAID), antibiotics, antiretroviral drugs and carbamazepine. Various sources of pharmaceuticals in the environment are reported, with WWTPs found as the major contributor to their occurrence in South African rivers. Notably, a NSAID, ibuprofen, with concentrations found exceeding 100 μg L-1 in selected WWTPs has also been found at high levels reaching 60 μg L-1 in river water. Mostly, pharmaceuticals detected in wastewater are also reported in corresponding rivers. The present review details pharmaceuticals that should be included in environmental monitoring studies performed in South Africa, while also identifying areas for future research through the research gap analysis.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a05
R. Alsaiari, E. Musa, M. Rizk
Biodiesel is considered to be more friendly to the environment than petroleum-based fuels, cheaper and capable for producing greener energy which contributed positively in boosting bio-economy. In this work, waste cooking oil (WCO) is converted into biodiesel utilizing a waste eggshell (CaO) nano-catalyst in an effort to discover environmentally beneficial and economically viable processes for social and economic development. The eggshell-based CaO catalyst developed for the production of ecologically friendly biodiesel at a reduced price is calcined at temperatures between 600 and 1100 °C. The synthesized catalysts were assessed in terms of their physical and chemical qualities via BET, TGA and XRD analysis. This revealed that, besides displaying exceptional transesterification activity, the catalyst synthesised at 950 °C also offered the greatest biodiesel yield. Transesterification, used in biodiesel generation, was used to evaluate the catalytic performance of manufactured catalysts under several reaction circumstances. Under prime reaction conditions i.e., a reaction time of 3 hours, an ethanol-oil molar ratio of 9:1, and a catalyst amount of 4 wt.%, it was ascertained that a catalyst which had calcined at 950 °C demonstrated excellent transesterification activity and delivered a ceiling yield of 88% fatty acid ethyl esters. The production of FAME was confirmed by using gas chromatography-mass spectroscopy (GC-MS). Fuel properties of fatty acid ethyl ester complied with ASTM D 6751 which indicated that it would be an appropriate alternative form of fuel.
生物柴油被认为比石油基燃料对环境更友好，价格更便宜，能够产生更绿色的能源，对促进生物经济做出了积极的贡献。在这项工作中，利用废蛋壳(CaO)纳米催化剂将废食用油(WCO)转化为生物柴油，努力发现有利于环境和经济上可行的社会和经济发展的工艺。在600 ~ 1100℃的温度下煅烧的蛋壳型CaO催化剂用于生产低成本的生态友好型生物柴油。通过BET、TGA和XRD分析对合成的催化剂进行了理化性质评定。这表明，除了表现出优异的酯交换活性外，在950°C下合成的催化剂也提供了最大的生物柴油产率。生物柴油生产中使用的酯交换反应，在不同的反应条件下评价了所制备催化剂的催化性能。在最佳反应条件下，即反应时间为3小时，乙醇-油摩尔比为9:1，催化剂用量为4wt .%，确定了950℃煅烧的催化剂具有良好的酯交换活性，最高收率为88%脂肪酸乙酯。采用气相色谱-质谱联用(GC-MS)验证了FAME的生成。脂肪酸乙酯的燃料性能符合ASTM D 6751的要求，是一种合适的替代燃料。
{"title":"Effects of calcination temperature of eggshell-derived CaO as a catalyst for biodiesel production from waste cooking oil","authors":"R. Alsaiari, E. Musa, M. Rizk","doi":"10.17159/0379-4350/2023/v77a05","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a05","url":null,"abstract":"Biodiesel is considered to be more friendly to the environment than petroleum-based fuels, cheaper and capable for producing greener energy which contributed positively in boosting bio-economy. In this work, waste cooking oil (WCO) is converted into biodiesel utilizing a waste eggshell (CaO) nano-catalyst in an effort to discover environmentally beneficial and economically viable processes for social and economic development. The eggshell-based CaO catalyst developed for the production of ecologically friendly biodiesel at a reduced price is calcined at temperatures between 600 and 1100 °C. The synthesized catalysts were assessed in terms of their physical and chemical qualities via BET, TGA and XRD analysis. This revealed that, besides displaying exceptional transesterification activity, the catalyst synthesised at 950 °C also offered the greatest biodiesel yield. Transesterification, used in biodiesel generation, was used to evaluate the catalytic performance of manufactured catalysts under several reaction circumstances. Under prime reaction conditions i.e., a reaction time of 3 hours, an ethanol-oil molar ratio of 9:1, and a catalyst amount of 4 wt.%, it was ascertained that a catalyst which had calcined at 950 °C demonstrated excellent transesterification activity and delivered a ceiling yield of 88% fatty acid ethyl esters. The production of FAME was confirmed by using gas chromatography-mass spectroscopy (GC-MS). Fuel properties of fatty acid ethyl ester complied with ASTM D 6751 which indicated that it would be an appropriate alternative form of fuel.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a04
T. Umumararungu, M. Isaacs, H. Hoppe, E. Goosen, S. Khanye
This study explored a series of resorcinol derivatives originally identified as heat shock protein 90 inhibitors for activity against protozoan parasites. The repurposing of this series revealed that some of these compounds are active against chloroquine-sensitive Plasmodium falciparum (3D7) and Trypanosoma brucei brucei strains with IC50 values below 10 μM without obvious cytotoxic effects against human cervix adenocarcinoma (HeLa) cells at 25 μM.
{"title":"Re-screening and preliminary in vitro evaluation of resorcinol based Hsp90 inhibitors for potential protocidal activity","authors":"T. Umumararungu, M. Isaacs, H. Hoppe, E. Goosen, S. Khanye","doi":"10.17159/0379-4350/2023/v77a04","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a04","url":null,"abstract":"This study explored a series of resorcinol derivatives originally identified as heat shock protein 90 inhibitors for activity against protozoan parasites. The repurposing of this series revealed that some of these compounds are active against chloroquine-sensitive Plasmodium falciparum (3D7) and Trypanosoma brucei brucei strains with IC50 values below 10 μM without obvious cytotoxic effects against human cervix adenocarcinoma (HeLa) cells at 25 μM.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a02
Jonathan B Hay, K. A. Villiers, Dale Taylor, Tania Olivier, W. V. Otterlo, Margaret AL Blackie
Two series of coupled heterocyclic systems have been synthesised and found to be efficacious against the NF54 chloroquine sensitive strain of P. falciparum in an in vitro assay. Quinolines were coupled with benzofurans in the first series and benzothiophenes in the second series. Compounds with an amide linkage are more efficacious by one order of magnitude than the ester equivalent. No other clear pattern was discernible. Compounds were also tested for toxicity using an MTT assay. All compounds tested showed selectivity towards P. falciparum. Barring one, all compounds tested showed greater efficacy than chloroquine against β-hematin inhibition. But no correlation was observed between β-hematin inhibition and efficacy against P. falciparum.
{"title":"Quinoline-benzofuran and quinoline-benzothiophene derivatives as antiplasmodium agents","authors":"Jonathan B Hay, K. A. Villiers, Dale Taylor, Tania Olivier, W. V. Otterlo, Margaret AL Blackie","doi":"10.17159/0379-4350/2023/v77a02","DOIUrl":"https://doi.org/10.17159/0379-4350/2023/v77a02","url":null,"abstract":"Two series of coupled heterocyclic systems have been synthesised and found to be efficacious against the NF54 chloroquine sensitive strain of P. falciparum in an in vitro assay. Quinolines were coupled with benzofurans in the first series and benzothiophenes in the second series. Compounds with an amide linkage are more efficacious by one order of magnitude than the ester equivalent. No other clear pattern was discernible. Compounds were also tested for toxicity using an MTT assay. All compounds tested showed selectivity towards P. falciparum. Barring one, all compounds tested showed greater efficacy than chloroquine against β-hematin inhibition. But no correlation was observed between β-hematin inhibition and efficacy against P. falciparum.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.17159/0379-4350/2023/v77a07
K. Mashale, B. May, J. Sehata, J. Tshilongo, L. Chimuka
In this study, a South African mine tailing sample was characterized for base metals using X-Ray fluorescence, alkaline fusion, and acid digestion to subsequently evaluate the uncertainties involved. This was based on the importance of characterization data in subsequent methods and obtaining confidence in such methods. It was determined that instrument repeatability and reproducibility contributed most to the overall uncertainty. At a coverage factor of 2 (k=2), the measurement result for iron through alkaline fusion, XRF, and acid digestion was found to be 3.476 ± 0.026%, 3.835 ± 0.023%, and 3.741 ± 0.020%, respectively, and that of arsenic were 88 ± 11 mg kg-1 and 85.5 ± 8.3 mg kg-1 for fusion and acid digestion, respectively. Based on the calculated expanded uncertainties which are at an average of 0.8% of the measurement results, the three methods can be associated with high statistical confidence and therefore eases decision-making regarding subsequent analytical methods.
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