Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230016
Daniel G. S. Quattrociocchi, Thiago de M. Lima
{"title":"Catalytic Hydrogenation Reactions of Lignocellulosic Biomass-derived Compounds as a Strategy to Obtain Value-added Products","authors":"Daniel G. S. Quattrociocchi, Thiago de M. Lima","doi":"10.21577/1984-6835.20230016","DOIUrl":"https://doi.org/10.21577/1984-6835.20230016","url":null,"abstract":"","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75734113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230043
Luis Eduardo C. S. Machado, Igor M. Brito, João Victor S. B. Mello, Mauricio A. Melo
.
．
{"title":"Solar Light as the Energy Source for the Generation of Clean and Renewable Fuel: A View on the Photoelectrocatalytic Water Splitting","authors":"Luis Eduardo C. S. Machado, Igor M. Brito, João Victor S. B. Mello, Mauricio A. Melo","doi":"10.21577/1984-6835.20230043","DOIUrl":"https://doi.org/10.21577/1984-6835.20230043","url":null,"abstract":".","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72883364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230035
Fabiola R. O. do Nascimento, Jaqueline P. Rosado, Rafael C. Mori
meta-historiographical
meta-historiographical
{"title":"“Chemistry among Us“, by João Martins Teixeira: A Short Analysis and Transcription of a Pioneer Text on the History of Chemistry (Teaching) in Brazil","authors":"Fabiola R. O. do Nascimento, Jaqueline P. Rosado, Rafael C. Mori","doi":"10.21577/1984-6835.20230035","DOIUrl":"https://doi.org/10.21577/1984-6835.20230035","url":null,"abstract":"meta-historiographical","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90371799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230018
Analu F. de S. Brito, Thalisson A. de Souza, Laiane C. O. Pereira, César A. G. Dantas, Yuri M. do Nascimento, Maria de F. Agra, Alecksandra V. de Lacerda, R. Braz-Filho, Marcelo S. da Silva, Josean F. Tavares, Lucas S. Abreu
Mandacaru ( Cereus jamacaru ) is a Cactaceae species widely used as food and for medicinal purposes in Brazilian’s northeastern region. Nevertheless, only a few alkaloids were identified from this plant. Hence, the knowledge regarding their chemical diversity remains scarce. In view of the importance of mandacaru for Brazilian semiarid region this work aimed to reinvestigate the chemical composition of C. jamacaru applying modern phytochemical tools. To achieve this main goal, the extract of the cladodes was obtained and chromatographed over Sephadex LH-20. After that, the main fractions were analyzed by High Pressure Liquid Chromatograph (HPLC) and Mass Spectrometry (MS). These analyses combined allowed the detection of two saponins, jamacarusides A and B, which were isolated and fully characterized based on 1D and 2D Nuclear Magnetic Resonance (NMR) and high resolution mass spectrometry (HRMS) data, as well as their fragmentation patterns obtained from HPLC-ESI-MS/MS. In summary, this work contributed to extend the current knowledge about the chemical composition of Cereus jamacaru and cactaceae family.
{"title":"Novel Tritepene Saponins from Mandacaru (Cereus jamacaru)","authors":"Analu F. de S. Brito, Thalisson A. de Souza, Laiane C. O. Pereira, César A. G. Dantas, Yuri M. do Nascimento, Maria de F. Agra, Alecksandra V. de Lacerda, R. Braz-Filho, Marcelo S. da Silva, Josean F. Tavares, Lucas S. Abreu","doi":"10.21577/1984-6835.20230018","DOIUrl":"https://doi.org/10.21577/1984-6835.20230018","url":null,"abstract":"Mandacaru ( Cereus jamacaru ) is a Cactaceae species widely used as food and for medicinal purposes in Brazilian’s northeastern region. Nevertheless, only a few alkaloids were identified from this plant. Hence, the knowledge regarding their chemical diversity remains scarce. In view of the importance of mandacaru for Brazilian semiarid region this work aimed to reinvestigate the chemical composition of C. jamacaru applying modern phytochemical tools. To achieve this main goal, the extract of the cladodes was obtained and chromatographed over Sephadex LH-20. After that, the main fractions were analyzed by High Pressure Liquid Chromatograph (HPLC) and Mass Spectrometry (MS). These analyses combined allowed the detection of two saponins, jamacarusides A and B, which were isolated and fully characterized based on 1D and 2D Nuclear Magnetic Resonance (NMR) and high resolution mass spectrometry (HRMS) data, as well as their fragmentation patterns obtained from HPLC-ESI-MS/MS. In summary, this work contributed to extend the current knowledge about the chemical composition of Cereus jamacaru and cactaceae family.","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81964178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230056
Vanessa Nascimento, Helena Mannochio-Russo, Alan Cesar Pilon, Aldo Sena de Oliveira
{"title":"The Science Developed by Young Researchers in Brazil – Part 2","authors":"Vanessa Nascimento, Helena Mannochio-Russo, Alan Cesar Pilon, Aldo Sena de Oliveira","doi":"10.21577/1984-6835.20230056","DOIUrl":"https://doi.org/10.21577/1984-6835.20230056","url":null,"abstract":"","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135312415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.21577/1984-6835.20230040
Milena Araújo Agra, Jaqueline Evangelista de Queiroz, Plínio Lázaro Faleiro Naves, Gilberto Lúcio Benedito de Aquino
Chalcones are natural compounds formed by an α , β -unsaturated carbonyl system that joins two aromatic rings forming the central core of many biologically important compounds. They are the biogenetic precursors of flavonoids and isoflavonoids found abundantly in plants. The chalcone class is of great interest not only from a biosynthetic perspective
{"title":"Synthesis and Characterization of Fluorinated Derivatives of Chalcona","authors":"Milena Araújo Agra, Jaqueline Evangelista de Queiroz, Plínio Lázaro Faleiro Naves, Gilberto Lúcio Benedito de Aquino","doi":"10.21577/1984-6835.20230040","DOIUrl":"https://doi.org/10.21577/1984-6835.20230040","url":null,"abstract":"Chalcones are natural compounds formed by an α , β -unsaturated carbonyl system that joins two aromatic rings forming the central core of many biologically important compounds. They are the biogenetic precursors of flavonoids and isoflavonoids found abundantly in plants. The chalcone class is of great interest not only from a biosynthetic perspective","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136137195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21577/1984-6835.20220084
Cassia Cristina Fernandes, Mayker Lazaro Dantas Miranda
can invest in them. Findings in the literature led to the discussion of the development of some types of films made from biopolymers, additives and natural bioactive compounds. Researchers bet on films and edible coatings not only because their physico-chemical characteristics are effective to protect food but also because their development is easy. Finally, another strength is that the raw material needed to develop them, such as starch, is highly available.
{"title":"Films and Edible Coatings in the Development of Biodegradable Packaging: Sustainable and Eco‑friendly Alternatives","authors":"Cassia Cristina Fernandes, Mayker Lazaro Dantas Miranda","doi":"10.21577/1984-6835.20220084","DOIUrl":"https://doi.org/10.21577/1984-6835.20220084","url":null,"abstract":"can invest in them. Findings in the literature led to the discussion of the development of some types of films made from biopolymers, additives and natural bioactive compounds. Researchers bet on films and edible coatings not only because their physico-chemical characteristics are effective to protect food but also because their development is easy. Finally, another strength is that the raw material needed to develop them, such as starch, is highly available.","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75193046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21577/1984-6835.20220137
Bárbara Cristina Dias, João Flávio da Silveira Petruci
{"title":"Optoelectronic Nose: A Powerful Tool for the Discrimination of Volatile Mixtures","authors":"Bárbara Cristina Dias, João Flávio da Silveira Petruci","doi":"10.21577/1984-6835.20220137","DOIUrl":"https://doi.org/10.21577/1984-6835.20220137","url":null,"abstract":"","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75665400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21577/1984-6835.20220048
Vinícius N. Silveira, Nayara Caroline M. Carvalho, Jéssica A. Oliveira, L. D. da Silva, Valéria A. Alves
Ascorbic acid (vitamin C) is essential to our body and can be found in leafy vegetables, legumes and fruits, as well as in natural and industrialized juices. The concentration of vitamin C present in long life juices is normally informed by the manufacturer on the package label. The objective of this work was to use an electroanalytical technique, cyclic voltammetry, to determine the concentration of vitamin C in long-life juices. From the dilution of a 100 mmol L -1 stock solution of ascorbic acid, the calibration curves were prepared by the method of external standards or of standard addition. Cyclic voltammograms (CVs) were recorded from 0 to +1.0 V, with v = 50 mV s -1 . The solutions were prepared in the presence of KCl 0.34 mol L -1 as supporting electrolyte, including the samples. Measurements were taken in triplicate. It was found that vitamin C is present in all juice brands analyzed, and in some cases in a concentration very different from the value informed on the package label by the manufacturer. The present work showed the viability of using the CV technique for the determination of vitamin C in a food product, which is relevant for the teaching of electrochemistry.
抗坏血酸(维生素C)对我们的身体至关重要，它可以在绿叶蔬菜、豆类和水果以及天然和工业果汁中找到。保质期长的果汁中维生素C的含量通常由生产商在包装标签上标明。这项工作的目的是使用电分析技术，循环伏安法，以确定长寿命果汁中维生素C的浓度。用100 mmol L -1抗坏血酸原液稀释后，采用外标法或标准品加入法制备校准曲线。在0 ~ +1.0 V范围内记录循环伏安图(cv)， V = 50 mV s -1。溶液以KCl 0.34 mol L -1作为支撑电解质制备，包括样品。测量一式三份。研究发现，在所分析的所有果汁品牌中都含有维生素C，在某些情况下，维生素C的浓度与制造商在包装标签上标明的值大不相同。本研究证明了利用CV技术测定食品中维生素C的可行性，对电化学教学具有一定的指导意义。
{"title":"Determination of Ascorbic Acid in Long Life Juices by Cyclic Voltammetry Using External Standards and Standard Addition Methods: An Experimental Proposal for Teaching Analytical Instrumental Chemistry","authors":"Vinícius N. Silveira, Nayara Caroline M. Carvalho, Jéssica A. Oliveira, L. D. da Silva, Valéria A. Alves","doi":"10.21577/1984-6835.20220048","DOIUrl":"https://doi.org/10.21577/1984-6835.20220048","url":null,"abstract":"Ascorbic acid (vitamin C) is essential to our body and can be found in leafy vegetables, legumes and fruits, as well as in natural and industrialized juices. The concentration of vitamin C present in long life juices is normally informed by the manufacturer on the package label. The objective of this work was to use an electroanalytical technique, cyclic voltammetry, to determine the concentration of vitamin C in long-life juices. From the dilution of a 100 mmol L -1 stock solution of ascorbic acid, the calibration curves were prepared by the method of external standards or of standard addition. Cyclic voltammograms (CVs) were recorded from 0 to +1.0 V, with v = 50 mV s -1 . The solutions were prepared in the presence of KCl 0.34 mol L -1 as supporting electrolyte, including the samples. Measurements were taken in triplicate. It was found that vitamin C is present in all juice brands analyzed, and in some cases in a concentration very different from the value informed on the package label by the manufacturer. The present work showed the viability of using the CV technique for the determination of vitamin C in a food product, which is relevant for the teaching of electrochemistry.","PeriodicalId":21315,"journal":{"name":"Revista Virtual de Química","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74626897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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