cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.19945297.v1
title: DEVELOPMENT AND VALIDATION OF A FAST AND SIMPLE HPLC-UV METHOD TO DETERMINE CAFFEINE IN GUARANA (Paullinia cupana) FOOD SUPPLEMENTS

description: Caffeine and guarana are safe foods according to the American (FDA) and Brazilian (ANVISA) health agencies. However, data regarding the composition, quality, and safety of guarana-based food supplements sold in Brazil are limited. Most of the methods used for quantification of caffeine and other guarana chemical markers are based on complex extraction techniques as well as on gradient elution and do not evaluate the matrix effect nor the uncertainty estimation measurement. A simple and selective method for caffeine detection has been developed and validated using HPLC-UV. It shows linearity between 1 and 10 µg mL-1, has a significant matrix effect (p &lt; 0.05) and its expanded uncertainty varies from 6.9 to 16.7%. Other parameters (selectivity, recovery, precision, robustness, limits of detection, and quantification) were satisfactory. The present study has analyzed 30 commercial samples of guarana-based food supplements (powders and capsules). Powder samples have shown an average caffeine level of 25.27 ± 5.20 mg g-1 while capsules 28.53 ± 13.81 mg g-1. No significant difference between the two types of samples has been observed (p &gt; 0.005).
DOI: 10.6084/m9.figshare.19945298
title: MICROPLASTICS: ENVIRONMENTAL OCCURRENCE AND ANALYTICAL CHALLENGES

description: Plastic pollution is a major societal, economic, and environmental issue. Upon release into the environment, plastics are altered by biological and physicochemical processes that influence their fate and transport within ecosystems. Large plastic debris can fragment into smaller pieces and are called microplastics (MPs) when occurring at sizes between 1 µm and 5 mm, fragmented or produced in this range. These small pieces of plastics are ubiquitous anthropogenic contaminants found throughout the world; however, the environmental consequences and effects on biota are not clearly understood. Scientific literature on the environmental implications of MP pollution is expanding rapidly and critical review of this literature is necessary to identify areas of evolving consensus and remaining gaps in knowledge. Herein a comprehensive literature review was performed to assess (i) the sources and distribution of MPs in different environmental compartments, (ii) the analytical methods that have been applied worldwide, and the key analytical challenges that remain in assessing MPs in the environment, and, finally, (iii) to integrate the findings of Brazilian MP research, which showed that since 2004 (80 papers up to 2020) has documented the presence of MPs in aquatic matrices and sediments with focus on marine ecosystems, mainly identified by visual inspection.
DOI: 10.6084/m9.figshare.19945298.v1
title: MICROPLASTICS: ENVIRONMENTAL OCCURRENCE AND ANALYTICAL CHALLENGES

description: Plastic pollution is a major societal, economic, and environmental issue. Upon release into the environment, plastics are altered by biological and physicochemical processes that influence their fate and transport within ecosystems. Large plastic debris can fragment into smaller pieces and are called microplastics (MPs) when occurring at sizes between 1 µm and 5 mm, fragmented or produced in this range. These small pieces of plastics are ubiquitous anthropogenic contaminants found throughout the world; however, the environmental consequences and effects on biota are not clearly understood. Scientific literature on the environmental implications of MP pollution is expanding rapidly and critical review of this literature is necessary to identify areas of evolving consensus and remaining gaps in knowledge. Herein a comprehensive literature review was performed to assess (i) the sources and distribution of MPs in different environmental compartments, (ii) the analytical methods that have been applied worldwide, and the key analytical challenges that remain in assessing MPs in the environment, and, finally, (iii) to integrate the findings of Brazilian MP research, which showed that since 2004 (80 papers up to 2020) has documented the presence of MPs in aquatic matrices and sediments with focus on marine ecosystems, mainly identified by visual inspection.
DOI: 10.6084/m9.figshare.19945303
title: CONTRIBUTIONS TO CHEMISTRY TEACHER EDUCATION FOR ACTION IN NON-FORMAL EDUCATIONAL SETTING: ANALYTICAL FRAMEWORK AS AN EVALUATION FACILITATOR

description: This work presents an analytical framework focusing on the evaluation of contributions of formative actions to teaching practice. It consists of thirteen indicators, distributed into four levels, The framework was developed from analyzing participants’ final assignment, who attended a Specialization Course in Teaching Methodology in Natural Sciences, offered in a non-formal education setting. Potentialities and limitations related to the teacher education framework are discussed, as well as its application in the context of teaching chemistry.
DOI: 10.6084/m9.figshare.19945303.v1
title: CONTRIBUTIONS TO CHEMISTRY TEACHER EDUCATION FOR ACTION IN NON-FORMAL EDUCATIONAL SETTING: ANALYTICAL FRAMEWORK AS AN EVALUATION FACILITATOR

description: This work presents an analytical framework focusing on the evaluation of contributions of formative actions to teaching practice. It consists of thirteen indicators, distributed into four levels, The framework was developed from analyzing participants’ final assignment, who attended a Specialization Course in Teaching Methodology in Natural Sciences, offered in a non-formal education setting. Potentialities and limitations related to the teacher education framework are discussed, as well as its application in the context of teaching chemistry.
DOI: 10.6084/m9.figshare.19945307
title: LOW-COST SYSTEM FOR ONLINE MONITORING OF PHOTOCALYTICAL REACTIONS: APPLICATION IN NITRO-PHENOL

description: There is a global concern with pollutants and organic contaminants and efficient and inexpensive methods are sought for the treatment of these toxic products. Generally, large volume reactors and the use of expensive equipment are required to monitor a photoreaction. The present work proposes the construction of a colorimetric equipment, which allows the online monitoring of photoreactions, using low-cost materials that allow the analysis from small aliquots. To show the applicability of the system, we studied the reduction reaction of 4-nitrophenol (4NP) with NaBH4. The impedimetric sensor enabled to construct the kinetic curve of the decrease in the chromophore band. It was possible to observe that the 4NP reduction reaction depends on: (i) chromophore concentration; (ii) stability of the reducing agent and; (iii) repulsion between the anions. The system developed here opens doors, as it can be used using a photocatalyst in the form of film, and it has also proved to be an inexpensive alternative for both research and teaching laboratories, as it allows the execution of chemical physics practices such as kinetic monitoring of reactions and mathematical adjustment of the curves.
DOI: 10.6084/m9.figshare.19945307.v1
title: LOW-COST SYSTEM FOR ONLINE MONITORING OF PHOTOCALYTICAL REACTIONS: APPLICATION IN NITRO-PHENOL

description: There is a global concern with pollutants and organic contaminants and efficient and inexpensive methods are sought for the treatment of these toxic products. Generally, large volume reactors and the use of expensive equipment are required to monitor a photoreaction. The present work proposes the construction of a colorimetric equipment, which allows the online monitoring of photoreactions, using low-cost materials that allow the analysis from small aliquots. To show the applicability of the system, we studied the reduction reaction of 4-nitrophenol (4NP) with NaBH4. The impedimetric sensor enabled to construct the kinetic curve of the decrease in the chromophore band. It was possible to observe that the 4NP reduction reaction depends on: (i) chromophore concentration; (ii) stability of the reducing agent and; (iii) repulsion between the anions. The system developed here opens doors, as it can be used using a photocatalyst in the form of film, and it has also proved to be an inexpensive alternative for both research and teaching laboratories, as it allows the execution of chemical physics practices such as kinetic monitoring of reactions and mathematical adjustment of the curves.
DOI: 10.6084/m9.figshare.19945312
title: PROMOTING EXPLANATORY MODELS ON FELODIPINE-CYTOCHROME P450 INTERACTION: A DIDACTIC PROPOSAL MODELING-BASED

description: This article presents the results of the study of explanatory models produced by 81 students of first-year of medicine at the Universidad del Norte in Barranquilla-Colombia. The students face a case in the area of chemistry applied to medicine, through a contextualized problem situation (SPC), constructed from a perspective of teaching chemistry in context. The explanatory models generated by the students were analyzed qualitatively at four moments of the implementation of a teaching proposal. The results obtained at the beginning of the implementation of the proposal indicate that the students did not elaborate any type of explanatory model. However, these arised from the teaching proposal that involves the SPC in which the students begin to generate explanatory models supported by chemistry content and categorized mostly in the research as Descriptive and Interpretative, a situation fostered by the theoretical and methodological coherence of the SPC, which was designed from a perspective of teaching in context based on modeling and leveraged by scaffolding.
DOI: 10.6084/m9.figshare.19945313
title: CARTESIAN AXIS AND PLANE CONVENTIONS IN Cnv SYMMETRY GROUPS

description: In this work, we call the attention to the ambiguity found in the literature when labeling vibrations and molecular orbitals as B1 and B2 for molecules belonging to the C2v point group as, for example, the water molecule. A survey of several books and some articles shows that this ambiguity comes from a long time ago and persists today, being a source of misunderstanding and a waste of time for students and teachers. It means that, in the case of the point groups Cnv, Dn, and Dnh (n = 2, 4, 6), it is very important to draw students’ attention to this ambiguity that exists in the literature. It is unfortunate that the recommendation made by Mulliken, more than sixty years ago, to always place the water molecule in the yz plane, has not been followed.
DOI: 10.6084/m9.figshare.19945313.v1
title: CARTESIAN AXIS AND PLANE CONVENTIONS IN Cnv SYMMETRY GROUPS

description: In this work, we call the attention to the ambiguity found in the literature when labeling vibrations and molecular orbitals as B1 and B2 for molecules belonging to the C2v point group as, for example, the water molecule. A survey of several books and some articles shows that this ambiguity comes from a long time ago and persists today, being a source of misunderstanding and a waste of time for students and teachers. It means that, in the case of the point groups Cnv, Dn, and Dnh (n = 2, 4, 6), it is very important to draw students’ attention to this ambiguity that exists in the literature. It is unfortunate that the recommendation made by Mulliken, more than sixty years ago, to always place the water molecule in the yz plane, has not been followed.
DOI: 10.6084/m9.figshare.19945312.v1
title: PROMOTING EXPLANATORY MODELS ON FELODIPINE-CYTOCHROME P450 INTERACTION: A DIDACTIC PROPOSAL MODELING-BASED

description: This article presents the results of the study of explanatory models produced by 81 students of first-year of medicine at the Universidad del Norte in Barranquilla-Colombia. The students face a case in the area of chemistry applied to medicine, through a contextualized problem situation (SPC), constructed from a perspective of teaching chemistry in context. The explanatory models generated by the students were analyzed qualitatively at four moments of the implementation of a teaching proposal. The results obtained at the beginning of the implementation of the proposal indicate that the students did not elaborate any type of explanatory model. However, these arised from the teaching proposal that involves the SPC in which the students begin to generate explanatory models supported by chemistry content and categorized mostly in the research as Descriptive and Interpretative, a situation fostered by the theoretical and methodological coherence of the SPC, which was designed from a perspective of teaching in context based on modeling and leveraged by scaffolding.
DOI: 10.6084/m9.figshare.19945318
title: Exergy and emergy: complementary tools for assessing the environmental sustainability use of biosolids generated in wastewater-treatment plant for energy-production

description: Taking advantage of the energy contained in the biosolids generated in a wastewater treatment plant (WWTP) is one of the processes of greatest interest due to the opportunity to obtain an energy resources from a waste. The aim of this research was to analyze the environmental sustainability use of biosolids generated in a wastewater-treatment plant for energy-production by fluidized-bed gasification under exergy analysis. The energy-production system was based on previous studies of sustainable-emergy alternatives using biosolids. Sustainability of the process was evaluated by identifying stages in the energy-production system (from drying application to electricity generation) where it is possible to reduce useful energy losses as well as identifying the value of waste streams within the system through exergy analysis. It was illustrated the destroyed exergy and the efficiency by stage and by product in order to assess the effects of inefficiencies in the process sustainability. The mixture of biosolids with coal was identified as a highly sustainable stage of the process, as it presents the highest index of exergy sustainability (0.99), in contrast to the stages of energy-transformation (turbine) and gas-cleaning, which efficiencies are 0.17 and 0.4, respectively. Energy-transformation and gas-cleaning stages are of interest in terms of an improved energy recovery process, making it more efficient by applying new technologies and/or using the waste streams that have high energy potentials.
DOI: 10.6084/m9.figshare.19945322
title: FROM FAME TO OSTRACISM: EIGHT REAGENTS THAT LEFT THE LABORATORY ENVIRONMENT

description: Historical aspects related to eight reagents that were present in analytical chemistry laboratories in the first decades of the twentieth century are described. They have peculiarities that are based on their curious names or the purposes for which they were intended. Their presence in the laboratory environment reflected their industrial applications and the chemical analysis procedures used at that time. From the mid XXth century, with the migration of qualitative analysis to the chemistry teaching, these reagents have been replaced by others that today serve the same purposes as those previously used. However, many of them still retain their industrial importance. This historical overview emphasizes the importance of the evolution of chemicals and chemical assays for security and efficiency reasons. Learning from past experiences develops a critical spirit and laboratory behavior more committed to occupational hygiene and safety, without losing sight the learning power that qualitative analytical chemistry offers.
DOI: 10.6084/m9.figshare.19945322.v1
title: FROM FAME TO OSTRACISM: EIGHT REAGENTS THAT LEFT THE LABORATORY ENVIRONMENT

description: Historical aspects related to eight reagents that were present in analytical chemistry laboratories in the first decades of the twentieth century are described. They have peculiarities that are based on their curious names or the purposes for which they were intended. Their presence in the laboratory environment reflected their industrial applications and the chemical analysis procedures used at that time. From the mid XXth century, with the migration of qualitative analysis to the chemistry teaching, these reagents have been replaced by others that today serve the same purposes as those previously used. However, many of them still retain their industrial importance. This historical overview emphasizes the importance of the evolution of chemicals and chemical assays for security and efficiency reasons. Learning from past experiences develops a critical spirit and laboratory behavior more committed to occupational hygiene and safety, without losing sight the learning power that qualitative analytical chemistry offers.
DOI: 10.6084/m9.figshare.19945324
title: Zeólita NaA sintetizada sobre fibra de vidro como estratégia para otimização do abrandamento de águas duras

description: NaA ZEOLITE SYNTHESIZED OVER FIBERGLASS AS A STRATEGY FOR OPTIMIZING HARD WATER SOFTENING. Zeolite NaA has been successfully synthesized over glass fiber surface previously activated by alkaline treatment. By varying the time of the treatment and the amount of silica and alumina precursors used in the reaction mixture, a sample with higher zeolite concentration could be obtained. This material was evaluated for water softening process as an alternative substitute for the use of the zeolite in its powder form, in which several drawbacks related to recovery and reuse limit its application. Water softening experiments, carried out in a continuous flow system, with a column containing the glass fiber-zeolite NaA, showed high performance in decreasing the Ca2+ ions, with complete removal achieved for 20 mL of simulated hard water (Ca2+ 100.0 mg L-1) by using 200 mg of the sample in form of column (10 mm diameter × 300 mm high). The sample maintained this performance in a wide range of pH (3.0-9.0), and also presented a feasible regenerability, with no decrease in its performance during the first four cycles of use, reaching 87.3% of efficiency over the tenth cycle.
DOI: 10.6084/m9.figshare.19945324.v1
title: Zeólita NaA sintetizada sobre fibra de vidro como estratégia para otimização do abrandamento de águas duras

description: NaA ZEOLITE SYNTHESIZED OVER FIBERGLASS AS A STRATEGY FOR OPTIMIZING HARD WATER SOFTENING. Zeolite NaA has been successfully synthesized over glass fiber surface previously activated by alkaline treatment. By varying the time of the treatment and the amount of silica and alumina precursors used in the reaction mixture, a sample with higher zeolite concentration could be obtained. This material was evaluated for water softening process as an alternative substitute for the use of the zeolite in its powder form, in which several drawbacks related to recovery and reuse limit its application. Water softening experiments, carried out in a continuous flow system, with a column containing the glass fiber-zeolite NaA, showed high performance in decreasing the Ca2+ ions, with complete removal achieved for 20 mL of simulated hard water (Ca2+ 100.0 mg L-1) by using 200 mg of the sample in form of column (10 mm diameter × 300 mm high). The sample maintained this performance in a wide range of pH (3.0-9.0), and also presented a feasible regenerability, with no decrease in its performance during the first four cycles of use, reaching 87.3% of efficiency over the tenth cycle.
DOI: 10.6084/m9.figshare.19945325
title: Eco-friendly multivariant green analytical technique for the estimation of ketoconazole by UV spectroscopy in bulk and cream formulation

description: The pharmaceutical industries are focusing on Green Analytical Chemistry principles like miniaturization, eco-friendly solvent usage, waste recycling, and analyst safety for sustainable results. A simple, eco-friendly sensitive and effective extraction and multivariant green analytical method to estimate ketoconazole in bulk and cream formulation were developed and validated according to International Council for Harmonisation (ICH) guidelines. Based on the multivariant analytical technique, the developed method built in linear regression equations between concentration and absorbance with seven different wavelengths. The validation results represent the method has linear at a concentration of 12.8-19.2 μg mL-1 with calculated Limit of Detection (LOD) and Limit of Quantification (LOQ) of 0.338 and 1.026 μg mL-1, respectively. The method results representing a precise accuracy, inter-day, and intraday precision in all the wavelengths with percentage Relative Standard Deviation (RSD) under the limits as less than 2. Also, the method was tested with two different marketed ketoconazole cream formulations with a satisfactory result. The results of the proposed method replicated the novelty in classic approaches and proved statistically. This method was confirmed as greenest than previous methods reported by using assessing tools like National Environmental Method Index (NEMI), Green Analytical Procedure Index (GAPI), Analytical eco-scale, and Analytical Greenness (AGREE) metrics. As a result, the proposed approach could widely utilize for an efficient green analytical methodology for the estimation of ketoconazole.
DOI: 10.6084/m9.figshare.19945325.v1
title: Eco-friendly multivariant green analytical technique for the estimation of ketoconazole by UV spectroscopy in bulk and cream formulation

description: The pharmaceutical industries are focusing on Green Analytical Chemistry principles like miniaturization, eco-friendly solvent usage, waste recycling, and analyst safety for sustainable results. A simple, eco-friendly sensitive and effective extraction and multivariant green analytical method to estimate ketoconazole in bulk and cream formulation were developed and validated according to International Council for Harmonisation (ICH) guidelines. Based on the multivariant analytical technique, the developed method built in linear regression equations between concentration and absorbance with seven different wavelengths. The validation results represent the method has linear at a concentration of 12.8-19.2 μg mL-1 with calculated Limit of Detection (LOD) and Limit of Quantification (LOQ) of 0.338 and 1.026 μg mL-1, respectively. The method results representing a precise accuracy, inter-day, and intraday precision in all the wavelengths with percentage Relative Standard Deviation (RSD) under the limits as less than 2. Also, the method was tested with two different marketed ketoconazole cream formulations with a satisfactory result. The results of the proposed method replicated the novelty in classic approaches and proved statistically. This method was confirmed as greenest than previous methods reported by using assessing tools like National Environmental Method Index (NEMI), Green Analytical Procedure Index (GAPI), Analytical eco-scale, and Analytical Greenness (AGREE) metrics. As a result, the proposed approach could widely utilize for an efficient green analytical methodology for the estimation of ketoconazole.