Pub Date : 2023-06-26DOI: 10.21577/0100-4042.20230028
A. Sobreira, Janderson B.L. de Albuquerque, Wallace de Queiroz, P. de Souza, D. Fernandes, M. de Souza
Malvaceae sensu lato is a family containing about 245 genera and 4,465 species mainly distributed across tropical and subtropical regions worldwide. Species of this family usually contain alkaloids with anti-inflammatory, antinociceptive, antiparasitic, antimicrobial and anticancer properties due to its secondary metabolites. In this context, this review aims to checklist the alkaloids isolated from Malvaceae sensu lato species, evaluating their chemical profile and pharmacological potential, providing a broad and concise overview of these secondary metabolites. The results were collected from scientific databases such as Web of Science, Scifinder, Pubmed, ScienceDirect and Google Scholar, using the keywords “Alkaloids” and “Malvaceae”. Several pharmacological/ biological activities are reported in literature for the most varied alkaloid nuclei, such as: vasorelaxation of the mesentery of rats (cryptolepinone), antitrypanosomal activity (waltherione) and anti-inflammatory and bronchodilator activity (vasicine), which highlights a succession of activities related to this class of secondary metabolites. Presented data report the importance of the Malvaceae sensu lato family, demonstrating the biological relevance of its alkaloids, in order to contribute to scientific knowledge and the development of new drugs.
Malvaceae sensu lato是一个科，有245属4465种，主要分布在热带和亚热带地区。由于其次生代谢产物，本科植物通常含有具有抗炎、抗炎、抗寄生虫、抗菌和抗癌特性的生物碱。在此背景下，本综述旨在检查从Malvaceae sensu lato物种中分离的生物碱，评估其化学特征和药理潜力，为这些次生代谢产物提供一个广泛而简洁的概述。研究结果收集自Web of Science、Scifinder、Pubmed、ScienceDirect和b谷歌Scholar等科学数据库，检索关键词为“Alkaloids”和“Malvaceae”。文献报道了几种不同生物碱核的药理学/生物学活性，例如:大鼠肠系膜的血管松弛(隐肾上腺素)，抗锥虫活性(瓦西里酮)和抗炎和支气管扩张活性(瓦西里嗪)，这突出了与这类次级代谢物相关的一系列活性。提出的数据报告了Malvaceae sensu lato家族的重要性，展示了其生物碱的生物学相关性，以促进科学知识和新药的开发。
{"title":"PHYTOCHEMICAL AND PHARMACOLOGICAL ASPECTS OF THE ALKALOIDS OF MALVACEAE sensu lato SPECIES: A REVIEW","authors":"A. Sobreira, Janderson B.L. de Albuquerque, Wallace de Queiroz, P. de Souza, D. Fernandes, M. de Souza","doi":"10.21577/0100-4042.20230028","DOIUrl":"https://doi.org/10.21577/0100-4042.20230028","url":null,"abstract":"Malvaceae sensu lato is a family containing about 245 genera and 4,465 species mainly distributed across tropical and subtropical regions worldwide. Species of this family usually contain alkaloids with anti-inflammatory, antinociceptive, antiparasitic, antimicrobial and anticancer properties due to its secondary metabolites. In this context, this review aims to checklist the alkaloids isolated from Malvaceae sensu lato species, evaluating their chemical profile and pharmacological potential, providing a broad and concise overview of these secondary metabolites. The results were collected from scientific databases such as Web of Science, Scifinder, Pubmed, ScienceDirect and Google Scholar, using the keywords “Alkaloids” and “Malvaceae”. Several pharmacological/ biological activities are reported in literature for the most varied alkaloid nuclei, such as: vasorelaxation of the mesentery of rats (cryptolepinone), antitrypanosomal activity (waltherione) and anti-inflammatory and bronchodilator activity (vasicine), which highlights a succession of activities related to this class of secondary metabolites. Presented data report the importance of the Malvaceae sensu lato family, demonstrating the biological relevance of its alkaloids, in order to contribute to scientific knowledge and the development of new drugs.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271172","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 : 2023-06-26DOI: 10.21577/0100-4042.20230038
A. Cobre, B. Böger, M. Fachi, C. Ehrenfried, D. Stremel, E. D. de Melo, F. Tonin, R. Pontarolo
To identify natural bioactive compounds (NBCs) as potential inhibitors of spike (S1) by means of in silico assays. NBCs with previously proven biological in vitro activity were obtained from the ZINC database and analyzed through virtual screening and molecular docking to identify those with higher affinity to the spike protein. Eight machine learning models were used to validate the results: Principal Component Analysis (PCA), Artificial Neural Network (ANN), Support Vector Machine (SVM), k-Nearest Neighbors (KNN), Partial Least Squares-Discriminant Analysis (PLS-DA), Gradient Boosted Tree Discriminant Analysis (XGBoostDA), Soft Independent Modelling of Class Analogies (SIMCA) and Logistic Regression Discriminate Analysis (LREG). Selected NBCs were submitted to drug-likeness prediction using Lipinski’s and Veber’s rule of five. A prediction of pharmacokinetic parameters and toxicity was also performed (ADMET). Antivirals currently used for COVID-19 (remdesivir and molnupiravir) were used as a comparator. A total of 170,906 compounds were analyzed. Of these, 34 showed greater affinity with the S1 (affinity energy < -7 kcal mol-1). Most of these compounds belonged to the class of coumarins (benzopyrones), presenting a benzene ring fused to a lactone (group of heterosides). The PLS-DA model was able to reproduce the results of the virtual screening and molecular docking (accuracy of 97.0%). Of the 34 compounds, only NBC5 (feselol), NBC14, NBC15 and NBC27 had better results in ADMET predictions. These had similar binding affinity to S1 when compared to remdesivir and molnupirvir. Feselol and three other NBCs were the most promising candidates for treating COVID-19. In vitro and in vivo studies are needed to confirm these findings.
{"title":"MACHINE LEARNING-BASED VIRTUAL SCREENING, MOLECULAR DOCKING, DRUG-LIKENESS, PHARMACOKINETICS AND TOXICITY ANALYSES TO IDENTIFY NEW NATURAL INHIBITORS OF THE GLYCOPROTEIN SPIKE (S1) OF SARS-CoV-2","authors":"A. Cobre, B. Böger, M. Fachi, C. Ehrenfried, D. Stremel, E. D. de Melo, F. Tonin, R. Pontarolo","doi":"10.21577/0100-4042.20230038","DOIUrl":"https://doi.org/10.21577/0100-4042.20230038","url":null,"abstract":"To identify natural bioactive compounds (NBCs) as potential inhibitors of spike (S1) by means of in silico assays. NBCs with previously proven biological in vitro activity were obtained from the ZINC database and analyzed through virtual screening and molecular docking to identify those with higher affinity to the spike protein. Eight machine learning models were used to validate the results: Principal Component Analysis (PCA), Artificial Neural Network (ANN), Support Vector Machine (SVM), k-Nearest Neighbors (KNN), Partial Least Squares-Discriminant Analysis (PLS-DA), Gradient Boosted Tree Discriminant Analysis (XGBoostDA), Soft Independent Modelling of Class Analogies (SIMCA) and Logistic Regression Discriminate Analysis (LREG). Selected NBCs were submitted to drug-likeness prediction using Lipinski’s and Veber’s rule of five. A prediction of pharmacokinetic parameters and toxicity was also performed (ADMET). Antivirals currently used for COVID-19 (remdesivir and molnupiravir) were used as a comparator. A total of 170,906 compounds were analyzed. Of these, 34 showed greater affinity with the S1 (affinity energy < -7 kcal mol-1). Most of these compounds belonged to the class of coumarins (benzopyrones), presenting a benzene ring fused to a lactone (group of heterosides). The PLS-DA model was able to reproduce the results of the virtual screening and molecular docking (accuracy of 97.0%). Of the 34 compounds, only NBC5 (feselol), NBC14, NBC15 and NBC27 had better results in ADMET predictions. These had similar binding affinity to S1 when compared to remdesivir and molnupirvir. Feselol and three other NBCs were the most promising candidates for treating COVID-19. In vitro and in vivo studies are needed to confirm these findings.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271552","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 : 2023-06-26DOI: 10.21577/0100-4042.20230033
Wladmir da Silva, Carlos Filgueiras
GLASS AND ITS IMPORTANCE IN LIFE AND IN CHEMISTRY. Glass is one of the most important materials both in ordinary life, in which its presence is felt everywhere, as in the laboratory, be it a chemical or any other laboratory. This article discusses glass in many aspects, including its composition, or compositions, history and applications, both as a component of civilization as a practical and ordinary component in thousands of uses as an indispensable material. Also will be discussed many of its scientific applications, particularly in chemistry. A survey will also be presented of the origins and present state of glass techniques in Brazil.
{"title":"O VIDRO E SUA IMPORTÂNCIA NA VIDA E NA QUÍMICA","authors":"Wladmir da Silva, Carlos Filgueiras","doi":"10.21577/0100-4042.20230033","DOIUrl":"https://doi.org/10.21577/0100-4042.20230033","url":null,"abstract":"GLASS AND ITS IMPORTANCE IN LIFE AND IN CHEMISTRY. Glass is one of the most important materials both in ordinary life, in which its presence is felt everywhere, as in the laboratory, be it a chemical or any other laboratory. This article discusses glass in many aspects, including its composition, or compositions, history and applications, both as a component of civilization as a practical and ordinary component in thousands of uses as an indispensable material. Also will be discussed many of its scientific applications, particularly in chemistry. A survey will also be presented of the origins and present state of glass techniques in Brazil.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271219","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 : 2023-06-26DOI: 10.21577/0100-4042.20230032
Jamerson da Silva, André Galembeck, Mônica Belian, Wagner Silva, Jandyson Santos, Jacinto Silva Neto, J. Aguiar, T. Gonçalves
A NEW DINUCLEAR COORDINATION COMPOUND DESIGNED TO HAVE NO OXIDATIVE DAMAGE AND TOXICOLOGICAL EFFECTS. The synthesis, characterization, acute toxicity, antitumor activity, and histopathological analysis of a novel dinuclear platinum(2+) complex − [Pt(DACH-κ2N)µ-(C4H2O6-κ4O)Pt(DACH-κ2N)] − is reported. Through acute toxicity tests, it was possible to place the platinum complexes into categories according to the OECD protocol. The dinuclear complex was classified in category 2 (cisplatin - category 1; and oxaliplatin - category 2). Analyzing the interaction between dsDNA and dinuclear complex was observed an Tm increase, suggesting that the dinuclear complex-dsDNA interact probably through of the interstrand form. Evaluations of tumor masses extracted from mice inoculated with Ehrlich carcinoma demonstrated a percent of tumor inhibition similar for cisplatin and oxaliplatin, but statistically different and superior for the case of the dinuclear complex. Cisplatin and oxaliplatin showed 41.4 and 40.8% inhibition, respectively, while the dinuclear complex presented 66.3%. The histopathological analysis demonstrated that the group treated with cisplatin showed more significant tissue damage, moderate hepatic steatosis, and nephritis. The livers, spleens, and kidneys of the animals treated with the dinuclear complex were within the normality range with no tissue lesions, and absence of metastasis.
{"title":"UM NOVO COMPOSTO DE COORDENAÇÃO DINUCLEAR PROJETADO PARA NÃO APRESENTAR DANOS OXIDATIVOS E EFEITOS TOXICOLÓGICOS","authors":"Jamerson da Silva, André Galembeck, Mônica Belian, Wagner Silva, Jandyson Santos, Jacinto Silva Neto, J. Aguiar, T. Gonçalves","doi":"10.21577/0100-4042.20230032","DOIUrl":"https://doi.org/10.21577/0100-4042.20230032","url":null,"abstract":"A NEW DINUCLEAR COORDINATION COMPOUND DESIGNED TO HAVE NO OXIDATIVE DAMAGE AND TOXICOLOGICAL EFFECTS. The synthesis, characterization, acute toxicity, antitumor activity, and histopathological analysis of a novel dinuclear platinum(2+) complex − [Pt(DACH-κ2N)µ-(C4H2O6-κ4O)Pt(DACH-κ2N)] − is reported. Through acute toxicity tests, it was possible to place the platinum complexes into categories according to the OECD protocol. The dinuclear complex was classified in category 2 (cisplatin - category 1; and oxaliplatin - category 2). Analyzing the interaction between dsDNA and dinuclear complex was observed an Tm increase, suggesting that the dinuclear complex-dsDNA interact probably through of the interstrand form. Evaluations of tumor masses extracted from mice inoculated with Ehrlich carcinoma demonstrated a percent of tumor inhibition similar for cisplatin and oxaliplatin, but statistically different and superior for the case of the dinuclear complex. Cisplatin and oxaliplatin showed 41.4 and 40.8% inhibition, respectively, while the dinuclear complex presented 66.3%. The histopathological analysis demonstrated that the group treated with cisplatin showed more significant tissue damage, moderate hepatic steatosis, and nephritis. The livers, spleens, and kidneys of the animals treated with the dinuclear complex were within the normality range with no tissue lesions, and absence of metastasis.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271666","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 : 2023-06-26DOI: 10.21577/0100-4042.20230022
Antonio Chepluki, T. Frizon, Igor Villares De Carvalho
DEVELOPMENT OF A SPIN COATING EQUIPMENT WITH A VACUUM SUBSTRATE FIXING SYSTEM USING REUSED MATERIALS. This work presents the development of a low-cost spin coater for thin film deposition as an alternative to commercial equipment that have high acquisition cost. The proposed spin coater uses a brushless motor taken from an unused hard disk, which is activated through the association of an electronic speed controller (ESC) and an Arduino microcontroller. During deposition, the rotating substrate is attached with a vacuum clamping system. For the control, the system uses a Hall effect sensor to read the engine speed. The rotation readings performed by the equipment sensor were validated with a tachometer. Finally, TiO2 films were deposited on glass substrates with ITO (Indium Tin Oxide) and characterized by UV-Vis spectroscopy to obtain the transmittance of the films at different rotation speeds.
{"title":"DESENVOLVIMENTO DE UM EQUIPAMENTO DE SPIN COATING COM SISTEMA DE FIXAÇÃO DE SUBSTRATO A VÁCUO EMPREGANDO MATERIAIS REUTILIZADOS","authors":"Antonio Chepluki, T. Frizon, Igor Villares De Carvalho","doi":"10.21577/0100-4042.20230022","DOIUrl":"https://doi.org/10.21577/0100-4042.20230022","url":null,"abstract":"DEVELOPMENT OF A SPIN COATING EQUIPMENT WITH A VACUUM SUBSTRATE FIXING SYSTEM USING REUSED MATERIALS. This work presents the development of a low-cost spin coater for thin film deposition as an alternative to commercial equipment that have high acquisition cost. The proposed spin coater uses a brushless motor taken from an unused hard disk, which is activated through the association of an electronic speed controller (ESC) and an Arduino microcontroller. During deposition, the rotating substrate is attached with a vacuum clamping system. For the control, the system uses a Hall effect sensor to read the engine speed. The rotation readings performed by the equipment sensor were validated with a tachometer. Finally, TiO2 films were deposited on glass substrates with ITO (Indium Tin Oxide) and characterized by UV-Vis spectroscopy to obtain the transmittance of the films at different rotation speeds.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270937","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 : 2023-06-26DOI: 10.21577/0100-4042.20230025
I. Feitosa, N. Munin, B. Goulart, Cassiana Montagner
OCCURRENCE OF PESTICIDES IN CLAY AND SANDY SOILS AFTER APPLICATION IN PASTURE AND SUGARCANE CROPS. Sugarcane is considered one of the greatest alternatives for the biofuels sector due to the high potential in the production of ethanol and its respective by-products. Processes of converting degraded pastures into sugarcane crops have been increasingly common in Brazil, as well as the use of pesticides to control plant diseases and pests in several crops. The objective of this work was to evaluate the occurrence of 2,4-D, ametryn, tebuthiuron, fipronil and its degradation products (fipronil sulfide and fipronil sulfone) in clay and sandy soils when applied to pasture and sugarcane management. Solid-liquid extraction and liquid chromatography coupled to mass spectrometry were used to quantify the compounds. The optimized method was validated with the following parameters: linear range from 0.5 to 300 μg L-1; linearity (r) > 0.99; precision with CV from 1.0 to 15.0%; accuracy of 60 to 117%, instrumental limit of detection (LOD) from 0.1 to 1.0 μg L-1 and instrumental limit of quantification (LOQ) of 0.5 μg L-1 for all pesticides, except 2,4-D (5.0 μg L-1). Pesticides concentrations of the experimental farms ranged from 0.1 to 266 μg kg-1, with the highest concentrations found in the months of pesticide’s application. The results showed the persistence of some pesticides in the soils even after months of use.
{"title":"OCORRÊNCIA DE AGROTÓXICOS EM SOLOS ARGILOSOS E ARENOSOS APÓS APLICAÇÃO EM PASTAGENS E CANA-DE-AÇÚCAR","authors":"I. Feitosa, N. Munin, B. Goulart, Cassiana Montagner","doi":"10.21577/0100-4042.20230025","DOIUrl":"https://doi.org/10.21577/0100-4042.20230025","url":null,"abstract":"OCCURRENCE OF PESTICIDES IN CLAY AND SANDY SOILS AFTER APPLICATION IN PASTURE AND SUGARCANE CROPS. Sugarcane is considered one of the greatest alternatives for the biofuels sector due to the high potential in the production of ethanol and its respective by-products. Processes of converting degraded pastures into sugarcane crops have been increasingly common in Brazil, as well as the use of pesticides to control plant diseases and pests in several crops. The objective of this work was to evaluate the occurrence of 2,4-D, ametryn, tebuthiuron, fipronil and its degradation products (fipronil sulfide and fipronil sulfone) in clay and sandy soils when applied to pasture and sugarcane management. Solid-liquid extraction and liquid chromatography coupled to mass spectrometry were used to quantify the compounds. The optimized method was validated with the following parameters: linear range from 0.5 to 300 μg L-1; linearity (r) > 0.99; precision with CV from 1.0 to 15.0%; accuracy of 60 to 117%, instrumental limit of detection (LOD) from 0.1 to 1.0 μg L-1 and instrumental limit of quantification (LOQ) of 0.5 μg L-1 for all pesticides, except 2,4-D (5.0 μg L-1). Pesticides concentrations of the experimental farms ranged from 0.1 to 266 μg kg-1, with the highest concentrations found in the months of pesticide’s application. The results showed the persistence of some pesticides in the soils even after months of use.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271119","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 : 2023-06-26DOI: 10.21577/0100-4042.20230024
M. Chiarello, Luana C. Crocoli, Vinícius B. Molon, S. Moura
Grapes are among the most widely cultivated fruits in the world, with the majority of Brazilian production focusing on natural grape juice. In this work, a total of 40 samples of 2 types of natural grape juice were analyzed for the presence of 86 pesticide residues, with multiresidue extraction based on modified QuEChERS, by liquid chromatography with high-resolution mass spectrometry (LC-HRMS). Limits of detection and quantification were below 6 μg L-1 and 20 μg L-1, RSD < 20%, R2 > 0.99 and recovery ranged from 80 and 120%. Thus, the developed method was validated and good performance characteristics such as linearity, trueness, repeatability and inter-day precision were obtained. As results, 7 pesticides were detected in real samples (azoxystrobin, benalaxyl, carbendazim, tebuconazol, thiophanate-methyl, pyriproxiphen and pyrimethanil). The method was successfully validated for simultaneous evaluation of 86 multiclass pesticides residues levels, which was applied in 40 natural white and red grape juice market samples. The limits of quantification (LOQs) were low enough and the method was tested on samples showing its applicability, and therefore, this method can be used in routine analysis. Also, this work therefore also serves as an alert regarding the contamination of processed products.
{"title":"PESTICIDES IN PROCESSED FOOD - MULTIRESIDUE PESTICIDES IN NATURAL GRAPE JUICES BY HIGHRESOLUTION MASS SPECTROMETRY","authors":"M. Chiarello, Luana C. Crocoli, Vinícius B. Molon, S. Moura","doi":"10.21577/0100-4042.20230024","DOIUrl":"https://doi.org/10.21577/0100-4042.20230024","url":null,"abstract":"Grapes are among the most widely cultivated fruits in the world, with the majority of Brazilian production focusing on natural grape juice. In this work, a total of 40 samples of 2 types of natural grape juice were analyzed for the presence of 86 pesticide residues, with multiresidue extraction based on modified QuEChERS, by liquid chromatography with high-resolution mass spectrometry (LC-HRMS). Limits of detection and quantification were below 6 μg L-1 and 20 μg L-1, RSD < 20%, R2 > 0.99 and recovery ranged from 80 and 120%. Thus, the developed method was validated and good performance characteristics such as linearity, trueness, repeatability and inter-day precision were obtained. As results, 7 pesticides were detected in real samples (azoxystrobin, benalaxyl, carbendazim, tebuconazol, thiophanate-methyl, pyriproxiphen and pyrimethanil). The method was successfully validated for simultaneous evaluation of 86 multiclass pesticides residues levels, which was applied in 40 natural white and red grape juice market samples. The limits of quantification (LOQs) were low enough and the method was tested on samples showing its applicability, and therefore, this method can be used in routine analysis. Also, this work therefore also serves as an alert regarding the contamination of processed products.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271062","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 : 2023-06-26DOI: 10.21577/0100-4042.20230027
B. Cerqueira, G. Lima, A. Mascarenhas, H. Andrade, Rodrigo De Paula
The experimental activities for undergraduate chemistry students play an important role to develop skills and expertise in that science thus, the practice-experimental classes are so important to achieve this purpose. This work deals with a demonstrative experience for dye separation from food coloring sample using liquid column chromatography. Beyond the experimental practice and the facility in visualizing the separation, this demonstration shows how a simple experiment involving alternative and easy access materials can promote a meaningful learning once it is possible to handle the acquired data, trace and analyze the results themselves, thus developing skills rather than the operational procedure. This proposal could be implemented in initial chemistry classes in Brazilian universities. Sea and river sands were used as stationary phases and aqueous ethanolic solutions were used as mobile phases. A food coloring (a mixture of 3 dyes) was chosen as sample to be studied. Chromatographic separation was followed by spectrophotometric measurements. A set of analyses were carried out to discuss the solubility of the food coloring, granulometric studies of the stationary phases used and electronic microscopy images of the sands studied here. As alternative materials were used in this work, a chromatographic column was also constructed with low-cost materials.
{"title":"LOW-COST AND EASY ACCESS MATERIALS FOR A LABORATORY CLASS: A PROPOSAL OF LIQUID CHROMATOGRAPHY FOR FOOD COLORING SEPARATION AS AN EXPERIENCE OF MEANINGFUL LEARNING","authors":"B. Cerqueira, G. Lima, A. Mascarenhas, H. Andrade, Rodrigo De Paula","doi":"10.21577/0100-4042.20230027","DOIUrl":"https://doi.org/10.21577/0100-4042.20230027","url":null,"abstract":"The experimental activities for undergraduate chemistry students play an important role to develop skills and expertise in that science thus, the practice-experimental classes are so important to achieve this purpose. This work deals with a demonstrative experience for dye separation from food coloring sample using liquid column chromatography. Beyond the experimental practice and the facility in visualizing the separation, this demonstration shows how a simple experiment involving alternative and easy access materials can promote a meaningful learning once it is possible to handle the acquired data, trace and analyze the results themselves, thus developing skills rather than the operational procedure. This proposal could be implemented in initial chemistry classes in Brazilian universities. Sea and river sands were used as stationary phases and aqueous ethanolic solutions were used as mobile phases. A food coloring (a mixture of 3 dyes) was chosen as sample to be studied. Chromatographic separation was followed by spectrophotometric measurements. A set of analyses were carried out to discuss the solubility of the food coloring, granulometric studies of the stationary phases used and electronic microscopy images of the sands studied here. As alternative materials were used in this work, a chromatographic column was also constructed with low-cost materials.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271164","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 : 2023-06-26DOI: 10.21577/0100-4042.20230037
Marco Lyrio, D. Debona, N. Conceição, Francisco Gomes, A. Pereira, Henrique Frizzera, Jéssica Reis, Taila Grecco, Bruna Pires, Valdemar Lacerda Jr., E. Castro, Marsele Isidoro, P. Filgueiras, W. Romão
COMPARING THE ANALYTICAL EFFICIENCY OF FTIR, UV-VIS, CLAE-DAD AND ESI(+)MS TECHNIQUES IN THE STUDY OF FOOD DYES. Food additives are chemical substances added to improve organoleptic characteristics, in this context, there are several synthetic dyes, such as sunset yellow, tartrazine, erioglaucine, allura red, indigo carmine, and new coccine, that can also be identified through different analytical techniques such as infrared spectroscopy, UV-Vis spectrophotometry, high performance liquid chromatography with diode array detector and mass spectrometry. Therefore, the objective of this work was to compare methods developed for different analytical techniques, in order to identify the one that presents greater efficiency in certain applications. For this, the patterns of the dyes were analyzed, as well as their mixtures and foods that had them. As a result, the CLAE-DAD presents excellent selectivity and linearity of the calibration curves, but it presents higher LD and LQ values when compared to the UV-Vis, in turn the infrared provides information regarding functional groups and bonds. Mass spectrometry showed great capabilities in identifying the molecular formula and better selectivity in the absence of the erioglaucine dye. It is not feasible to indicate the best or worst analytical approach, but it is possible to point out which one is more suitable for each application. Regarding the quantification capacity, chromatography and UV-Vis are good alternatives, but in mixtures containing more than one dye, CLAE-DAD is more suitable due to the better selectivity. Regarding the identification capacity, mass spectrometry, especially FT-ICR MS, is the most appropriate technique to propose molecular formulas due to its high resolution and mass accuracy. The advantage of FTIR was the easier sample preparation, being able to analyze the dyes in the solid state.
{"title":"COMPARANDO A EFICIÊNCIA ANALÍTICA DAS TÉCNICAS FTIR, UV-VIS, CLAE-DAD E ESI(+)MS NO ESTUDO DE CORANTES ALIMENTARES","authors":"Marco Lyrio, D. Debona, N. Conceição, Francisco Gomes, A. Pereira, Henrique Frizzera, Jéssica Reis, Taila Grecco, Bruna Pires, Valdemar Lacerda Jr., E. Castro, Marsele Isidoro, P. Filgueiras, W. Romão","doi":"10.21577/0100-4042.20230037","DOIUrl":"https://doi.org/10.21577/0100-4042.20230037","url":null,"abstract":"COMPARING THE ANALYTICAL EFFICIENCY OF FTIR, UV-VIS, CLAE-DAD AND ESI(+)MS TECHNIQUES IN THE STUDY OF FOOD DYES. Food additives are chemical substances added to improve organoleptic characteristics, in this context, there are several synthetic dyes, such as sunset yellow, tartrazine, erioglaucine, allura red, indigo carmine, and new coccine, that can also be identified through different analytical techniques such as infrared spectroscopy, UV-Vis spectrophotometry, high performance liquid chromatography with diode array detector and mass spectrometry. Therefore, the objective of this work was to compare methods developed for different analytical techniques, in order to identify the one that presents greater efficiency in certain applications. For this, the patterns of the dyes were analyzed, as well as their mixtures and foods that had them. As a result, the CLAE-DAD presents excellent selectivity and linearity of the calibration curves, but it presents higher LD and LQ values when compared to the UV-Vis, in turn the infrared provides information regarding functional groups and bonds. Mass spectrometry showed great capabilities in identifying the molecular formula and better selectivity in the absence of the erioglaucine dye. It is not feasible to indicate the best or worst analytical approach, but it is possible to point out which one is more suitable for each application. Regarding the quantification capacity, chromatography and UV-Vis are good alternatives, but in mixtures containing more than one dye, CLAE-DAD is more suitable due to the better selectivity. Regarding the identification capacity, mass spectrometry, especially FT-ICR MS, is the most appropriate technique to propose molecular formulas due to its high resolution and mass accuracy. The advantage of FTIR was the easier sample preparation, being able to analyze the dyes in the solid state.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271511","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 : 2023-05-29DOI: 10.21577/0100-4042.20230017
I. Sutjahja, Yuanita Sudarso, S. Ulhaq, Erik Yutomo
Hückel theory is a simple and powerful method for predicting the molecular orbital and the energy of conjugated molecules. However, the presence of nitrogen atoms in aza aromatic molecules alters the Coulomb and resonance integrals owing to the difference in electronegativity between nitrogen and carbon atoms. In this study, we focus on acridine and phenazine. Further correction is implemented based on the ring current model, thus revealing the change in resonance integral for the carbon–carbon bond along the bridge of the molecule. The Hamiltonian of the π–electron system in the Hückel method is solved using the HuLiS software. Various geometry-based aromaticity indices are used to obtain the aromaticity indices of the two non-equivalent rings. For further evaluation, the results for bond lengths are used to calculate the associated bond energy. Considering the carbon–hydrogen (CH) bonds, the total molecular energy is compared with the experimental heats of formation for a number of benzenoid hydrocarbons and aza aromatics, in addition to the two studied molecules. Finally, the correlation between the nitrogen atom on the aromaticity index and the ring energy content is evaluated to determine to which extent the Hückel model agrees with previous experimental and advanced computational studies.
h ckel理论是预测分子轨道和共轭分子能量的一种简单而有效的方法。然而，氮原子在含氮芳香分子中的存在，由于氮原子和碳原子之间电负性的差异，改变了库仑积分和共振积分。在本研究中，我们主要研究吖啶和非那嗪。基于环电流模型进行进一步校正，从而揭示了碳-碳键沿分子桥的共振积分的变化。利用HuLiS软件求解了 ckel法中π -电子体系的哈密顿量。利用各种基于几何的芳构指数得到了两个非等价环的芳构指数。为了进一步评估，键长结果用于计算相关键能。考虑到碳氢(CH)键，除了这两种研究的分子外，还将分子总能量与许多苯类烃和aza芳烃的实验生成热进行了比较。最后，评估了氮原子对芳香性指数与环能含量之间的相关性，以确定h ckel模型在多大程度上与先前的实验和先进的计算研究一致。
{"title":"AROMATICITY OF AZA AROMATIC MOLECULES: PREDICTION FROM HÜCKEL THEORY WITH MODIFIED PARAMETERS","authors":"I. Sutjahja, Yuanita Sudarso, S. Ulhaq, Erik Yutomo","doi":"10.21577/0100-4042.20230017","DOIUrl":"https://doi.org/10.21577/0100-4042.20230017","url":null,"abstract":"Hückel theory is a simple and powerful method for predicting the molecular orbital and the energy of conjugated molecules. However, the presence of nitrogen atoms in aza aromatic molecules alters the Coulomb and resonance integrals owing to the difference in electronegativity between nitrogen and carbon atoms. In this study, we focus on acridine and phenazine. Further correction is implemented based on the ring current model, thus revealing the change in resonance integral for the carbon–carbon bond along the bridge of the molecule. The Hamiltonian of the π–electron system in the Hückel method is solved using the HuLiS software. Various geometry-based aromaticity indices are used to obtain the aromaticity indices of the two non-equivalent rings. For further evaluation, the results for bond lengths are used to calculate the associated bond energy. Considering the carbon–hydrogen (CH) bonds, the total molecular energy is compared with the experimental heats of formation for a number of benzenoid hydrocarbons and aza aromatics, in addition to the two studied molecules. Finally, the correlation between the nitrogen atom on the aromaticity index and the ring energy content is evaluated to determine to which extent the Hückel model agrees with previous experimental and advanced computational studies.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270981","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}
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