Pub Date : 2023-06-23DOI: 10.21577/0103-5053.20230001
Arshad Ali, M. Hussain, M. Haseeb, M. Ashraf, Muhammad Farid-ul-Haq, T. Tabassum, Gulzar Muhammad, A. Abbas
Herein, a polysaccharide-based hydrogel from seeds of Salvia spinosa (SSH) was evaluated as a pH-responsive, superporous, hemocompatible, non-toxic, and sustained release material. The SSH-based tablets showed pH-dependent swelling (pH 7.4 > 6.8 > 4.5 > 1.2) as well as swelling and de-swelling behavior at pH 7.4 and 1.2, respectively. Sustained release of febuxostat was achieved by mimicking the gastrointestinal tract conditions for 14 h and following the zero-order kinetics and super case-II transport mechanism. Scanning electron microscopy revealed the porous nature of SSH even after compression. SSH was found to be hemocompatible with antioxidant properties. Acute toxicity studies ensured the safety of SSH at a maximum dose level of 2.0 g kg-1 body weight of the animals. SSH was also found as non-irritant to the eye. The histopathology of vital organs did not show any lesions or inflammation. Conclusively, SSH can be considered a safe ingredient for oral, dermal, and ophthalmic formulations.
{"title":"pH-Responsive, Hemocompatible, and Non-Toxic Polysaccharide-Based Hydrogel from Seeds of Salvia spinosa L. for Sustained Release of Febuxostat","authors":"Arshad Ali, M. Hussain, M. Haseeb, M. Ashraf, Muhammad Farid-ul-Haq, T. Tabassum, Gulzar Muhammad, A. Abbas","doi":"10.21577/0103-5053.20230001","DOIUrl":"https://doi.org/10.21577/0103-5053.20230001","url":null,"abstract":"Herein, a polysaccharide-based hydrogel from seeds of Salvia spinosa (SSH) was evaluated as a pH-responsive, superporous, hemocompatible, non-toxic, and sustained release material. The SSH-based tablets showed pH-dependent swelling (pH 7.4 > 6.8 > 4.5 > 1.2) as well as swelling and de-swelling behavior at pH 7.4 and 1.2, respectively. Sustained release of febuxostat was achieved by mimicking the gastrointestinal tract conditions for 14 h and following the zero-order kinetics and super case-II transport mechanism. Scanning electron microscopy revealed the porous nature of SSH even after compression. SSH was found to be hemocompatible with antioxidant properties. Acute toxicity studies ensured the safety of SSH at a maximum dose level of 2.0 g kg-1 body weight of the animals. SSH was also found as non-irritant to the eye. The histopathology of vital organs did not show any lesions or inflammation. Conclusively, SSH can be considered a safe ingredient for oral, dermal, and ophthalmic formulations.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68329128","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 : 2023-06-23DOI: 10.21577/0103-5053.20230011
X. Su, Lei Zhao, Xiangrui Wang, Zhao Wang, Zhichao Wang, Tao Shen, Ping Zhang
Different Al2O3 carriers were synthesized by co-precipitation and sol-gel method. From them, 4%NiO-20%MoO3/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 adsorption-desorption, NH3-temperature programmed desorption (TPD) and H2-temperature programmed reduction (TPR) and subsequently used for selective hydrogenation of naphthalene to high-value tetralin. The results showed that Ni-Mo/so-ge Al2O3 (900) exhibited better catalytic performance than Ni-Mo/commercial Al2O3, achieving 99.56% naphthalene conversion and 99.43% tetralin selectivity.
{"title":"Effect of Different Al2O3 Supports on the Synthesis of Tetralin by Selective Catalytic Hydrogenation of Naphthalene","authors":"X. Su, Lei Zhao, Xiangrui Wang, Zhao Wang, Zhichao Wang, Tao Shen, Ping Zhang","doi":"10.21577/0103-5053.20230011","DOIUrl":"https://doi.org/10.21577/0103-5053.20230011","url":null,"abstract":"Different Al2O3 carriers were synthesized by co-precipitation and sol-gel method. From them, 4%NiO-20%MoO3/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 adsorption-desorption, NH3-temperature programmed desorption (TPD) and H2-temperature programmed reduction (TPR) and subsequently used for selective hydrogenation of naphthalene to high-value tetralin. The results showed that Ni-Mo/so-ge Al2O3 (900) exhibited better catalytic performance than Ni-Mo/commercial Al2O3, achieving 99.56% naphthalene conversion and 99.43% tetralin selectivity.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68329430","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}
Designing highly efficient dialkylphosphinic acid extractant for zirconium/hafnium separation relies on systematic structure-property studies. In this paper, dialkylphosphinic acids with different substituents at β-C, γ-C and δ-C for zirconium and hafnium extraction and separation from H2SO4 media were investigated. The results show that substituents at β-C, γ-C and δ-C reduce the extraction ability of dialkylphosphinic acids for both zirconium and hafnium. The substituent effect at β-C is greater than that at γ-C and δ-C. The larger steric hindrance of the substituents (ethyl > methyl > H), the weaker extraction ability of the dialkylphosphinic acids. The zirconium and hafnium separation behavior is related to the extraction ability of dialkylphosphinic acids. Dialkylphosphinic acids with stronger extraction ability show better zirconium/hafnium separation performance at higher acidity of 2.0 mol L-1 H2SO4, while those with weaker extraction ability show better zirconium and hafnium separation performance at lower acidity of 0.25 mol L-1 H2SO4. The highest hafnium/zirconium separation factor (βHf/Zr) in the current study occurs with (2-ethylhexyl) (2,4,4-trimethylpentyl)phosphinic acid (USTB-1), which reaches 19.2.
{"title":"Selective Extraction of Hafnium over Zirconium with Dialkylphosphinic Acids from H2SO4 Media","authors":"Junlian Wang, Hui Liu, Wen Xu, Ziyong Chang, Pei-pei Wang, Huajun Wang","doi":"10.21577/0103-5053.20230014","DOIUrl":"https://doi.org/10.21577/0103-5053.20230014","url":null,"abstract":"Designing highly efficient dialkylphosphinic acid extractant for zirconium/hafnium separation relies on systematic structure-property studies. In this paper, dialkylphosphinic acids with different substituents at β-C, γ-C and δ-C for zirconium and hafnium extraction and separation from H2SO4 media were investigated. The results show that substituents at β-C, γ-C and δ-C reduce the extraction ability of dialkylphosphinic acids for both zirconium and hafnium. The substituent effect at β-C is greater than that at γ-C and δ-C. The larger steric hindrance of the substituents (ethyl > methyl > H), the weaker extraction ability of the dialkylphosphinic acids. The zirconium and hafnium separation behavior is related to the extraction ability of dialkylphosphinic acids. Dialkylphosphinic acids with stronger extraction ability show better zirconium/hafnium separation performance at higher acidity of 2.0 mol L-1 H2SO4, while those with weaker extraction ability show better zirconium and hafnium separation performance at lower acidity of 0.25 mol L-1 H2SO4. The highest hafnium/zirconium separation factor (βHf/Zr) in the current study occurs with (2-ethylhexyl) (2,4,4-trimethylpentyl)phosphinic acid (USTB-1), which reaches 19.2.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68329608","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 : 2023-06-23DOI: 10.21577/0103-5053.20230018
Joslaine Jacumazo, G. Parchen, M. Garcia, N. Santos, L. D. De Mio, F. Marques, R. D. de Freitas
Infections in fruits caused by fungi reduce the quantity and quality of food for human consumption, in addition to causing economic losses. In this sense, this study aimed to address the effects of eugenol nanocapsules (NCs) based on chitosan and carboxymethylcellulose in protecting nectarines against Monilinia fructicola, a brown rot agent, a worldwide important disease. NCs were prepared by layer-by-layer (LbL) self-assembly starting from an anionic template and deposition with up to two polymeric layers. The hydrodynamic diameters ranged from 158 nm (nanoemulsion), 360 nm (one polymeric layer) to 398 nm (two polymeric layers). NCs presented, during the in vitro release, the release of eugenol following a first order process. In addition to being in the region of stability (zeta potential ca. |30| mV), the capsules showed good adhesion to the nectarine surface. In relation to brown rot, the eugenol NCs with chitosan proved to be the best formulation compared to nanoemulsion and NCs with two polymeric layers for its control, increasing the probability that the fruits remain without symptoms, even after 7 days. Therefore, this study demonstrated that chitosan NCs containing eugenol could be an alternative to preserve fruit for longer periods in post-harvest.
{"title":"Nectarine Coated with Biopolymeric Nanocapsules Containing Eugenol to Control Brown Rot","authors":"Joslaine Jacumazo, G. Parchen, M. Garcia, N. Santos, L. D. De Mio, F. Marques, R. D. de Freitas","doi":"10.21577/0103-5053.20230018","DOIUrl":"https://doi.org/10.21577/0103-5053.20230018","url":null,"abstract":"Infections in fruits caused by fungi reduce the quantity and quality of food for human consumption, in addition to causing economic losses. In this sense, this study aimed to address the effects of eugenol nanocapsules (NCs) based on chitosan and carboxymethylcellulose in protecting nectarines against Monilinia fructicola, a brown rot agent, a worldwide important disease. NCs were prepared by layer-by-layer (LbL) self-assembly starting from an anionic template and deposition with up to two polymeric layers. The hydrodynamic diameters ranged from 158 nm (nanoemulsion), 360 nm (one polymeric layer) to 398 nm (two polymeric layers). NCs presented, during the in vitro release, the release of eugenol following a first order process. In addition to being in the region of stability (zeta potential ca. |30| mV), the capsules showed good adhesion to the nectarine surface. In relation to brown rot, the eugenol NCs with chitosan proved to be the best formulation compared to nanoemulsion and NCs with two polymeric layers for its control, increasing the probability that the fruits remain without symptoms, even after 7 days. Therefore, this study demonstrated that chitosan NCs containing eugenol could be an alternative to preserve fruit for longer periods in post-harvest.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68330030","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 : 2023-06-23DOI: 10.21577/0103-5053.20230013
G. Santos, F. Silva, J. Cruz-Filho, R. Luza, G. Luz Jr
Synthesis routes and parameters such as synthesis time, precursor molar ratio, pH, and temperature are critical for generating oxides of various sizes and morphological aspects. However, there is no information on how to prepare silver tungstate (Ag2WO4) crystals of different shapes and sizes under laboratory conditions and without using sulfating agents. In this study, we attempted to fill this gap by preparing α-Ag2WO4 crystals of various sizes and morphologies using the coprecipitation method in a 3 h interval at room temperature and without using sulfating agents. The powder X-ray diffraction analysis confirmed that all crystals had an orthorhombic structure, whereas Fourier-transform infrared spectroscopy revealed the degree of structural disorder in the bonds between the atoms in the materials. Scanning electron microscopy revealed that the α-Ag2WO4 crystals had different sizes (5.37-26.83 μm) and morphologies (tetragonal prism, rod, and cypress leave-like rod), whereas ultraviolet-visible diffuse reflectance spectroscopy analysis indicated the optical band gap energy (2.92-3.05 eV), calculated using the method proposed by Kubelka and Munk. Catalytic tests revealed that the synthesized samples with the smallest crystals (AW1) and a tetragonal prism morphology degraded dye more efficiently (apparent rate constant (k) = 5.86 × 10−3 min−1) than other samples.
{"title":"Silver Tungstate Obtained via Successive Seed Crystal Growth: Structural, Morphological, Optical, and Photocatalytic Properties","authors":"G. Santos, F. Silva, J. Cruz-Filho, R. Luza, G. Luz Jr","doi":"10.21577/0103-5053.20230013","DOIUrl":"https://doi.org/10.21577/0103-5053.20230013","url":null,"abstract":"Synthesis routes and parameters such as synthesis time, precursor molar ratio, pH, and temperature are critical for generating oxides of various sizes and morphological aspects. However, there is no information on how to prepare silver tungstate (Ag2WO4) crystals of different shapes and sizes under laboratory conditions and without using sulfating agents. In this study, we attempted to fill this gap by preparing α-Ag2WO4 crystals of various sizes and morphologies using the coprecipitation method in a 3 h interval at room temperature and without using sulfating agents. The powder X-ray diffraction analysis confirmed that all crystals had an orthorhombic structure, whereas Fourier-transform infrared spectroscopy revealed the degree of structural disorder in the bonds between the atoms in the materials. Scanning electron microscopy revealed that the α-Ag2WO4 crystals had different sizes (5.37-26.83 μm) and morphologies (tetragonal prism, rod, and cypress leave-like rod), whereas ultraviolet-visible diffuse reflectance spectroscopy analysis indicated the optical band gap energy (2.92-3.05 eV), calculated using the method proposed by Kubelka and Munk. Catalytic tests revealed that the synthesized samples with the smallest crystals (AW1) and a tetragonal prism morphology degraded dye more efficiently (apparent rate constant (k) = 5.86 × 10−3 min−1) than other samples.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68329563","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 : 2023-06-23DOI: 10.21577/0103-5053.20230062
N. Durán, W. Fávaro, S. Alborés, Thyerre da Costa, L. Tasić
Biogenic silver nanoparticles are synthesized through silver(I) reduction, which is promoted by biomolecules available in the biological world and mostly obtained from plant extracts, fungal bioproduction, and some bacteria. The exact mechanisms accounting for such oxidoreduction processes are not fully known. However, some studies have already mentioned oxidoreductases, cofactors (nicotinamide adenine dinucelotide hydrogen (NADH), dihydroflavine-adenine dinucleotid (FADH2)), and phenolic compounds, as the main reductive species engaged in the formation of silver(0) and silver nanoparticles (silver NPs) synthesis. Biosynthesis is a one-pot process that leads to stable silver NP colloids that, regarding their size, shape, and uniformity, can be successfully controlled; and show great stability when one takes into account their surface capping by some biomolecules that as well take part in their synthesis. Although great efforts have been made to feature capping biomolecules and their interactions with silver NP surfaces, knowledge of the quantity (exact number per cm2 ) and type of biomolecules that cap or surround silver NPs remains limited. The literature provides detailed information on protein capping, but it still shows gaps regarding many aspects of fine biophysical protein featuring. The reason why certain proteins prefer to interact with silver NP surface and form chemical bonds, whereas others rather have intermolecular interaction with the first layer of proteins remains unknown. Assessing capping proteins’ involvement in the bioactivity of biogenic silver NPs is another relevant research field. Certain proteins enhance bioactivity of silver NPs and lower toxicity; however, the way antimicrobial processes benefit from protein capping is yet to be discovered. Finally, biogenic silver NPs can be found both in the environment and in water; moreover, their additional activity and behavior must be known or, at least, hypothesized.
{"title":"Biogenic Silver Nanoparticles Capped with Proteins: Timed Knowledge and Perspectives","authors":"N. Durán, W. Fávaro, S. Alborés, Thyerre da Costa, L. Tasić","doi":"10.21577/0103-5053.20230062","DOIUrl":"https://doi.org/10.21577/0103-5053.20230062","url":null,"abstract":"Biogenic silver nanoparticles are synthesized through silver(I) reduction, which is promoted by biomolecules available in the biological world and mostly obtained from plant extracts, fungal bioproduction, and some bacteria. The exact mechanisms accounting for such oxidoreduction processes are not fully known. However, some studies have already mentioned oxidoreductases, cofactors (nicotinamide adenine dinucelotide hydrogen (NADH), dihydroflavine-adenine dinucleotid (FADH2)), and phenolic compounds, as the main reductive species engaged in the formation of silver(0) and silver nanoparticles (silver NPs) synthesis. Biosynthesis is a one-pot process that leads to stable silver NP colloids that, regarding their size, shape, and uniformity, can be successfully controlled; and show great stability when one takes into account their surface capping by some biomolecules that as well take part in their synthesis. Although great efforts have been made to feature capping biomolecules and their interactions with silver NP surfaces, knowledge of the quantity (exact number per cm2 ) and type of biomolecules that cap or surround silver NPs remains limited. The literature provides detailed information on protein capping, but it still shows gaps regarding many aspects of fine biophysical protein featuring. The reason why certain proteins prefer to interact with silver NP surface and form chemical bonds, whereas others rather have intermolecular interaction with the first layer of proteins remains unknown. Assessing capping proteins’ involvement in the bioactivity of biogenic silver NPs is another relevant research field. Certain proteins enhance bioactivity of silver NPs and lower toxicity; however, the way antimicrobial processes benefit from protein capping is yet to be discovered. Finally, biogenic silver NPs can be found both in the environment and in water; moreover, their additional activity and behavior must be known or, at least, hypothesized.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68338911","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 : 2023-05-26DOI: 10.21577/0103-5053.20220151
Jacira de Moura, M. Lage, Benedito B. Farias Filho, D. L. de Faria, Wilkins de Barros, Hugo Loureiro
The chemical-mineralogical characterization of rupestrian paintings in red, white, black and yellow colors, which decorate the rocky walls from the archaeological sites of Ema and Furna dos Índios (Inhuma, Piauí, Brazil) was performed. The chemical analyses were performed in situ by the non-invasive analytical technique X-ray fluorescence spectrometry (XRF) as well as in laboratory using a non-destructive approach, without previous sample preparation, and Raman microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) techniques. The results, when together, allowed unequivocal identification of the main substances responsible for the color pigments, namely, hematite (red pigment), gypsum (white pigment), amorphous carbon from charcoal (black pigment) and goethite (yellow pigment).
对在Ema和Furna dos Índios (Inhuma, Piauí，巴西)考古遗址的岩石墙壁上装饰的红色、白色、黑色和黄色的秘鲁绘画进行了化学矿物学表征。化学分析通过非侵入性分析技术x射线荧光光谱法(XRF)原位进行，以及在实验室使用非破坏性方法进行，无需事先制备样品，使用拉曼显微镜和扫描电子显微镜结合能量色散光谱(SEM-EDS)技术。这些结果结合在一起，可以明确地确定颜色颜料的主要物质，即赤铁矿(红色颜料)，石膏(白色颜料)，木炭中的无定形碳(黑色颜料)和针铁矿(黄色颜料)。
{"title":"Multi-Analytical Characterization of Rupestrian Precolonial Paintings of Inhuma, Piauí, Brazil","authors":"Jacira de Moura, M. Lage, Benedito B. Farias Filho, D. L. de Faria, Wilkins de Barros, Hugo Loureiro","doi":"10.21577/0103-5053.20220151","DOIUrl":"https://doi.org/10.21577/0103-5053.20220151","url":null,"abstract":"The chemical-mineralogical characterization of rupestrian paintings in red, white, black and yellow colors, which decorate the rocky walls from the archaeological sites of Ema and Furna dos Índios (Inhuma, Piauí, Brazil) was performed. The chemical analyses were performed in situ by the non-invasive analytical technique X-ray fluorescence spectrometry (XRF) as well as in laboratory using a non-destructive approach, without previous sample preparation, and Raman microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) techniques. The results, when together, allowed unequivocal identification of the main substances responsible for the color pigments, namely, hematite (red pigment), gypsum (white pigment), amorphous carbon from charcoal (black pigment) and goethite (yellow pigment).","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68328730","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 : 2023-05-26DOI: 10.21577/0103-5053.20220152
Denise Nóbrega, A. Lourenço, D. Fernandes, W. Lyra, E. Moreira, Paulo Henrique Diniz, Mario C U Araujo
Infusions of Mikania glomerata Sprengel (guaco) leaves are used in Brazil for the treatment of respiratory diseases. Coumarin is the chemical marker of guaco for quality control purposes. This work proposes a voltammetric methodology to determine coumarin by using a borondoped diamond electrode. At pH 10 (0.1 mol L-1 Britton-Robinson buffer solution), coumarin is irreversibly oxidized around +1.77 V in a process predominantly controlled by diffusion. The methodology described here presented a linear range from 1.54 to 15.3 μg mL-1 with limits of detection and quantification of 0.20 and 0.62 μg mL-1, respectively. Analysis of variance confirmed the significance of the regression and the absence of lack-of-fit at the confidence level of 95%. Infusion of commercial guaco leaves was directly analyzed, and results were in agreement with high-performance liquid chromatography after applying the paired t-test at a confidence level of 95%.
{"title":"Determination of Coumarin in Mikania glomerata Infusions by Square-Wave Voltammetry Using a Boron-Doped Diamond Electrode","authors":"Denise Nóbrega, A. Lourenço, D. Fernandes, W. Lyra, E. Moreira, Paulo Henrique Diniz, Mario C U Araujo","doi":"10.21577/0103-5053.20220152","DOIUrl":"https://doi.org/10.21577/0103-5053.20220152","url":null,"abstract":"Infusions of Mikania glomerata Sprengel (guaco) leaves are used in Brazil for the treatment of respiratory diseases. Coumarin is the chemical marker of guaco for quality control purposes. This work proposes a voltammetric methodology to determine coumarin by using a borondoped diamond electrode. At pH 10 (0.1 mol L-1 Britton-Robinson buffer solution), coumarin is irreversibly oxidized around +1.77 V in a process predominantly controlled by diffusion. The methodology described here presented a linear range from 1.54 to 15.3 μg mL-1 with limits of detection and quantification of 0.20 and 0.62 μg mL-1, respectively. Analysis of variance confirmed the significance of the regression and the absence of lack-of-fit at the confidence level of 95%. Infusion of commercial guaco leaves was directly analyzed, and results were in agreement with high-performance liquid chromatography after applying the paired t-test at a confidence level of 95%.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68328793","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 : 2023-05-26DOI: 10.21577/0103-5053.20220153
Laís Maroubo, W. Melchert
Sulfonamides (SAs) are low-cost synthetic antimicrobials widely used in veterinary and human medicine to treat diseases and prevent infections. However, long periods of exposure to sulfonamides can cause adverse effects such as allergic reactions. This work aims to study dispersive solid-liquid microextraction as an alternative method for extracting total SAs in meat samples. The procedure uses a colorimetric reaction based on the formation of a pink compound (imine salt) to determine total sulfonamides (sulfamethazine, sulfadimethoxine, sulfathiazole) with digital measurements. A linear response was observed between 33-233 μg kg-1 for total sulfonamides, and the coefficient of variation (n = 11; 67 μg kg-1 of total SAs) and the limit of detection were estimated to be 0.63% and 10 μg kg-1, respectively. For a 750 mg meat sample, 0.11 mg of 4-dimethylaminocinnamaldehyde, 2.60 mg of sodium dodecyl sulfate, and 275 μL of 1-butanol were consumed per sample, and consequently, generating only 335 μL of residue. Besides this, addition-recovery tests were performed, resulting in a 71-100% recovery range, indicating the trueness of the proposed method.
{"title":"Development of an Environmentally Friendly Extraction Method Using Smartphone-Based Digital Images for the Determination of Total Sulfonamides in Meat Samples","authors":"Laís Maroubo, W. Melchert","doi":"10.21577/0103-5053.20220153","DOIUrl":"https://doi.org/10.21577/0103-5053.20220153","url":null,"abstract":"Sulfonamides (SAs) are low-cost synthetic antimicrobials widely used in veterinary and human medicine to treat diseases and prevent infections. However, long periods of exposure to sulfonamides can cause adverse effects such as allergic reactions. This work aims to study dispersive solid-liquid microextraction as an alternative method for extracting total SAs in meat samples. The procedure uses a colorimetric reaction based on the formation of a pink compound (imine salt) to determine total sulfonamides (sulfamethazine, sulfadimethoxine, sulfathiazole) with digital measurements. A linear response was observed between 33-233 μg kg-1 for total sulfonamides, and the coefficient of variation (n = 11; 67 μg kg-1 of total SAs) and the limit of detection were estimated to be 0.63% and 10 μg kg-1, respectively. For a 750 mg meat sample, 0.11 mg of 4-dimethylaminocinnamaldehyde, 2.60 mg of sodium dodecyl sulfate, and 275 μL of 1-butanol were consumed per sample, and consequently, generating only 335 μL of residue. Besides this, addition-recovery tests were performed, resulting in a 71-100% recovery range, indicating the trueness of the proposed method.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68328883","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 : 2023-05-26DOI: 10.21577/0103-5053.20230043
Karine de Andrade, José Renato D Fajardo, Caio Leal, J. Carneiro, R. Fiorot
Humankind has experienced a remarkable development since it began to design and optimize chemical reactions to achieve valuable compounds. The key to accomplish these tasks is the proper understanding of how chemical transformations occur at a molecular level, that is, their reaction mechanisms. Based on a suitable mechanistic proposal, experimentalists choose a given chemical protocol to optimize experimental conditions, design new synthetic routes, and circumvent competing reactions. In this context, computational chemistry has become a valuable ally for mechanistic elucidation. We present herein a review of complementary collaborations between experimentalists and theoretical chemists to rationalize processes at the molecular level, focusing mainly on the fields of organic synthesis, natural product chemistry, and systems with environmental interest. Throughout this review, we highlight the ability of computational evaluations to provide answers to questions raised from experiments in a clear and direct way, indicating to experimentalists alternative paths to help them solve their problems.
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