Pub Date : 2023-04-04DOI: 10.30744/brjac.2179-3425.editorial.pvoliveira.n39
P. Oliveira
Analytical Chemistry has been consolidating itself over the years as a multidisciplinary area that has strong influence in the main branches of science. From the point of view of methods proposition, there are many unanswered questions that cannot do without analytical support. One of the great challenges is to meet some of the demands associated with sustainable development goals. The 17 sustainable development goals (SDGs) adopted by the United Nations Development Program since 2015 are “a universal call to action to end poverty, protect the planet, and ensure that by 2030 all people enjoy peace and prosperity”. The goals are ambitious and must balance social, economic, and environmental sustainability. Among the range of issues and challenges are the quality control of food, emerging microplastics pollution, nanoparticle and single particle determination, the control and removal of toxic elements and substances from environmental systems (water, soil, and air), and all chemical hazards that societies are exposed to today, which need attention and control. A quick observation of the 17 SDGs makes it possible to see how analytical chemistry can play an important role in fulfilling these challenging tasks. Over the years, analytical chemistry has evolved in such a way that the associated analytical techniques and methods are conducted quickly, safely, and with metrological quality. The creativity, knowhow, technology, and financial resources from all of society are necessary to achieve the SDGs in every context. This first volume of the 2023 BrJAC brings reflections and contributions that show adherence to some challenges mentioned above. The point of view of volatile species generation (VSG) for trace element and speciation analysis, including hydrides and different chemical structures, forming volatile species, such as carbonyls, alkyl-halides, and free atoms, nanoparticles, chelates, and oxides is a demonstration. The contribution on the preparation and use of miniaturized and low-cost electrochemical sensors shows the strength of this area, especially in the group of Brazilian scientists, and will undoubtedly contribute significantly to the identification of groups or different species or molecules. The review section shows the state of the art of capillary electrophoresis (CE) applied to human urine analysis for clinical diagnosis. The articles section covers auto-machine learning algorithms applied to vibrational spectroscopy data for the quality control of biodiesel; the determination of monomers of ethyl acrylate in commercial latex resin; spectrophotometric methods for the quality control of sodium diclofenac in tablets and lead-complex in vegetables using a new reagent for determination; and finally, a forensic contribution reporting a case of cocaine trafficking in asphaltic material. Enjoy and make good reading of the current issue!
{"title":"Sustainable Development Goals and Analytical Chemistry","authors":"P. Oliveira","doi":"10.30744/brjac.2179-3425.editorial.pvoliveira.n39","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.editorial.pvoliveira.n39","url":null,"abstract":"Analytical Chemistry has been consolidating itself over the years as a multidisciplinary area that has strong influence in the main branches of science. From the point of view of methods proposition, there are many unanswered questions that cannot do without analytical support. One of the great challenges is to meet some of the demands associated with sustainable development goals. The 17 sustainable development goals (SDGs) adopted by the United Nations Development Program since 2015 are “a universal call to action to end poverty, protect the planet, and ensure that by 2030 all people enjoy peace and prosperity”. The goals are ambitious and must balance social, economic, and environmental sustainability. Among the range of issues and challenges are the quality control of food, emerging microplastics pollution, nanoparticle and single particle determination, the control and removal of toxic elements and substances from environmental systems (water, soil, and air), and all chemical hazards that societies are exposed to today, which need attention and control. A quick observation of the 17 SDGs makes it possible to see how analytical chemistry can play an important role in fulfilling these challenging tasks. Over the years, analytical chemistry has evolved in such a way that the associated analytical techniques and methods are conducted quickly, safely, and with metrological quality. The creativity, knowhow, technology, and financial resources from all of society are necessary to achieve the SDGs in every context. This first volume of the 2023 BrJAC brings reflections and contributions that show adherence to some challenges mentioned above. The point of view of volatile species generation (VSG) for trace element and speciation analysis, including hydrides and different chemical structures, forming volatile species, such as carbonyls, alkyl-halides, and free atoms, nanoparticles, chelates, and oxides is a demonstration. The contribution on the preparation and use of miniaturized and low-cost electrochemical sensors shows the strength of this area, especially in the group of Brazilian scientists, and will undoubtedly contribute significantly to the identification of groups or different species or molecules. The review section shows the state of the art of capillary electrophoresis (CE) applied to human urine analysis for clinical diagnosis. The articles section covers auto-machine learning algorithms applied to vibrational spectroscopy data for the quality control of biodiesel; the determination of monomers of ethyl acrylate in commercial latex resin; spectrophotometric methods for the quality control of sodium diclofenac in tablets and lead-complex in vegetables using a new reagent for determination; and finally, a forensic contribution reporting a case of cocaine trafficking in asphaltic material. Enjoy and make good reading of the current issue!","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48925814","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 : 2023-04-04DOI: 10.30744/brjac.2179-3425.point-of-view-jkratzer.n39
J. Kratzer
The current concept of trace element analysis relies mainly on liquid nebulization to atomic spectrometric detectors characterized by a low sample introduction efficiency, typically reaching 5–8%. This is the bottleneck of all the common nebulizers regardless of the detector employed. As a consequence, more efficient approaches to analyte introduction into element-specific detectors, including atomic absorption (AAS), atomic fluorescence (AFS) and inductively coupled plasma (ICP) with either optical emission (OES) or mass spectrometry (MS) detection, have been sought. One of the strategies is volatile species generation (VSG) – a group of techniques based on analyte derivatization in order to form a volatile compound prior to spectrometric detection.1 Selective analyte conversion from liquid to gas phase results not only in enhanced analyte introduction efficiency but also in separation of the analyte from the sample matrix, leading to a reduced risk of interference.1 Additionally, VSG can employ substantially higher sample introduction flow rates than nebulization, further improving the resulting detection power. In principle, conversion of an analyte to the corresponding volatile compound can be achieved in three ways: chemically (C-VSG),1,2 electrochemically (Ec-VSG)3 or photochemically (P-VSG).4 Presently, hydride generation (HG) is the dominant and most explored VSG technique. However, HG is restricted to hydride-forming elements only, including thus ca eight analytes such as As, Se, Sb, Bi, Pb, Sn, Ge and Te.1 C-VSG, i.e. chemical reduction by means of NaBH4, is the most common approach to HG. Under the optimized conditions, the efficiency of chemical hydride generation (C-HG) reaches 100%, making this approach attractive for routine measurements. Owing to the benefits of the HG technique, effort has been made to expand the number of elements detectable by means of VSG to include volatile compounds other than binary hydrides. Generation of cold mercury vapors,1 i.e. free Hg atoms, is another example of a routinely used VSG technique, the popularity of which is comparable to that of HG. VSG-based approaches have been intensively explored in the last 15–20 years in order to make use of the benefits offered by VSG for elements other than hydride-forming elements and mercury. C-VSG and P-VSG have been employed as the most dominant strategies.2 Presently, successful VSG of more than 40 elements including transition and noble metals and even non-metals (S, P, Si, F, Cl, Br, I) has been reported.2 The volatile species generated are of different chemical structures including, e.g., carbonyls (Fe, Co, Ni, Mo, W), alkyl-halides (Cl, Br, I), free atoms (Cd), nanoparticles (Ag, Au, Cu, Pd), chelates (Pd) and oxides (Os). The recent challenges in the field of total element content determination at ultratrace levels by means of VSG lie in: 1) extending the VSG technique to new elements; 2) identifying the structure of the volatile species generated; 3) u
{"title":"Volatile Species Generation for Trace Element and Speciation Analysis – Current State and Future Perspectives","authors":"J. Kratzer","doi":"10.30744/brjac.2179-3425.point-of-view-jkratzer.n39","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.point-of-view-jkratzer.n39","url":null,"abstract":"The current concept of trace element analysis relies mainly on liquid nebulization to atomic spectrometric detectors characterized by a low sample introduction efficiency, typically reaching 5–8%. This is the bottleneck of all the common nebulizers regardless of the detector employed. As a consequence, more efficient approaches to analyte introduction into element-specific detectors, including atomic absorption (AAS), atomic fluorescence (AFS) and inductively coupled plasma (ICP) with either optical emission (OES) or mass spectrometry (MS) detection, have been sought. One of the strategies is volatile species generation (VSG) – a group of techniques based on analyte derivatization in order to form a volatile compound prior to spectrometric detection.1 Selective analyte conversion from liquid to gas phase results not only in enhanced analyte introduction efficiency but also in separation of the analyte from the sample matrix, leading to a reduced risk of interference.1 Additionally, VSG can employ substantially higher sample introduction flow rates than nebulization, further improving the resulting detection power. In principle, conversion of an analyte to the corresponding volatile compound can be achieved in three ways: chemically (C-VSG),1,2 electrochemically (Ec-VSG)3 or photochemically (P-VSG).4 Presently, hydride generation (HG) is the dominant and most explored VSG technique. However, HG is restricted to hydride-forming elements only, including thus ca eight analytes such as As, Se, Sb, Bi, Pb, Sn, Ge and Te.1 C-VSG, i.e. chemical reduction by means of NaBH4, is the most common approach to HG. Under the optimized conditions, the efficiency of chemical hydride generation (C-HG) reaches 100%, making this approach attractive for routine measurements. Owing to the benefits of the HG technique, effort has been made to expand the number of elements detectable by means of VSG to include volatile compounds other than binary hydrides. Generation of cold mercury vapors,1 i.e. free Hg atoms, is another example of a routinely used VSG technique, the popularity of which is comparable to that of HG. VSG-based approaches have been intensively explored in the last 15–20 years in order to make use of the benefits offered by VSG for elements other than hydride-forming elements and mercury. C-VSG and P-VSG have been employed as the most dominant strategies.2 Presently, successful VSG of more than 40 elements including transition and noble metals and even non-metals (S, P, Si, F, Cl, Br, I) has been reported.2 The volatile species generated are of different chemical structures including, e.g., carbonyls (Fe, Co, Ni, Mo, W), alkyl-halides (Cl, Br, I), free atoms (Cd), nanoparticles (Ag, Au, Cu, Pd), chelates (Pd) and oxides (Os). The recent challenges in the field of total element content determination at ultratrace levels by means of VSG lie in: 1) extending the VSG technique to new elements; 2) identifying the structure of the volatile species generated; 3) u","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47955556","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 : 2023-04-04DOI: 10.30744/brjac.2179-3425.interview.ivo.raimundo
Ivo Raimundo Jr
Ivo M. Raimundo Jr. holds a degree in chemistry (1983), a master’s degree in chemistry (1989), and a doctorate in analytical chemistry (1995), all from the Institute of Chemistry, University of Campinas (IQ-Unicamp), Brazil. He carried out postdoctoral studies at the University of Manchester Institute of Science and Technology (UMIST), Manchester, England (1997/98), and the University of South Carolina, Columbia, USA (2017). He is currently Associate Professor at the Department of Analytical Chemistry at IQ - Unicamp. He was Associate Director (2006–2009) and Director (2009–2015) of the Pluridisciplinary Center for Chemical, Biological and Agricultural Research (CPQBA) at Unicamp, Secretary of the Brazilian Chemical Society, Campinas Regional (2020-2022) and is currently its treasurer. He has served as an Associate Editor of the Journal of the Brazilian Chemical Society since 2019. Prof. Raimundo Jr has experience in instrumentation and automation in analytical chemistry, working mainly in the following areas: optical (nano)sensors, microfabrication of analytical systems, and laser-induced breakdown spectroscopy (LIBS).
Ivo M.Raimundo Jr.拥有化学学位（1983年）、化学硕士学位（1989年）和分析化学博士学位（1995年），均来自巴西坎皮纳斯大学化学研究所。他曾在英国曼彻斯特大学科技学院（UMIST）（1997/98）和美国哥伦比亚南卡罗来纳大学（2017）进行博士后研究。他目前是IQ-Unicamp分析化学系的副教授。他曾任联合国大学化学、生物和农业研究多学科中心（CPQBA）副主任（2006-2009年）和主任（2009-2015年），坎皮纳斯地区巴西化学学会秘书（2020-2022年），现任财务主管。自2019年以来，他一直担任《巴西化学学会杂志》副主编。Raimundo Jr教授在分析化学的仪器和自动化方面拥有丰富的经验，主要从事以下领域的工作：光学（纳米）传感器、分析系统的微制造和激光诱导击穿光谱（LIBS）。
{"title":"Professor Ivo M. Raimundo Jr., a researcher concerned about the current state of science in Brazil, kindly granted BrJAC an interview","authors":"Ivo Raimundo Jr","doi":"10.30744/brjac.2179-3425.interview.ivo.raimundo","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.interview.ivo.raimundo","url":null,"abstract":"Ivo M. Raimundo Jr. holds a degree in chemistry (1983), a master’s degree in chemistry (1989), and a doctorate in analytical chemistry (1995), all from the Institute of Chemistry, University of Campinas (IQ-Unicamp), Brazil. He carried out postdoctoral studies at the University of Manchester Institute of Science and Technology (UMIST), Manchester, England (1997/98), and the University of South Carolina, Columbia, USA (2017). He is currently Associate Professor at the Department of Analytical Chemistry at IQ - Unicamp. He was Associate Director (2006–2009) and Director (2009–2015) of the Pluridisciplinary Center for Chemical, Biological and Agricultural Research (CPQBA) at Unicamp, Secretary of the Brazilian Chemical Society, Campinas Regional (2020-2022) and is currently its treasurer. He has served as an Associate Editor of the Journal of the Brazilian Chemical Society since 2019. Prof. Raimundo Jr has experience in instrumentation and automation in analytical chemistry, working mainly in the following areas: optical (nano)sensors, microfabrication of analytical systems, and laser-induced breakdown spectroscopy (LIBS).","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49317811","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 : 2023-04-04DOI: 10.30744/brjac.2179-3425.letter-bcjanegitz.n39
B. Janegitz
Since the decade of the 90s when the first works of professor Joseph Wang were published, screen-printed electrodes have been proposed for many objectives. In the first works in Brazil a few years later, some authors proposed electrochemical sensors using graphite from batteries, which provide great results for the determination of several analytes.1 In another interesting work, Professor Lucio Angnes (USP) and collaborators prepared gold electrodes from CD, which presented a thin film of the noble metal.2 They obtained an extremely low-cost electrochemical sensor. After that, this research line gained notoriety in Brazil, and the number of groups and papers has increased considerably. In this regard, we can highlight some researchers that have been working on low-cost and disposable electrochemical sensors, including Lauro Kubota (UNICAMP), Luiz Humberto Marcolino Junior (UFPR), Márcio Fernando Bergamini (UFPR), Ronaldo Censi Faria (UFSCar), Éder Cavalheiro (USP), Osvaldo Novais de Oliveira Junior (USP), Sergio Spínola (USP), Murilo Santiago (CNPEM), Renato Souza Lima (CNPEM), Orlando Fatibello Filho (UFSCar), Wendell Coltro (USP), William Reis (UNICAMP), and Thiago Paixão (USP). The laboratory of Sensors, Nanomedicine, and Nanostructured Materials (LSNano) located at UFSCar Araras has also developed low-cost sensors using recyclable materials and conductive inks with simple preparation. Low-cost electrodes can be prepared with infinite possibilities by using different substrates, such as circuit boards,3 acetate sheets,4 and polyethylene terephthalate (PET) from bottles5 as well as paper6. In the last example, various types of papers have been applied in this area, including cardboard,7 waterproof,6 and adhesives8. Therefore, materials that we use daily can become important devices with great applications. There are many options to produce low-cost electrochemical sensors, including pencil drawing, stencil, laser scribing, and screen-printing techniques.9 The strategy depends on the subject and the materials that have been deposited to be used as conductors. In this context, the screen-printing technique is come from the t-shirt preparation and is an excellent alternative to produce hundreds of sensors in a few minutes. They can be applied by using different electrochemical techniques, such as potentiometry, voltammetry, and electrochemical impedance spectroscopy. For this purpose, low-cost inks, which are made of a polymer and a conductive material, are necessary. Conductive inks can be prepared with water based-polymers,10 nail polish,11 and traditional polymers based on organic solvents12. Otherwise, graphite carbon nanotubes and/or graphene and carbon dots have been used as conductive carbon-based materials.13 Also, metallic nanoparticles such as copper, platinum, and gold can be great alternatives for this intention but can be quite costly.
{"title":"Preparation and Use of Low-Cost Electrochemical Sensors","authors":"B. Janegitz","doi":"10.30744/brjac.2179-3425.letter-bcjanegitz.n39","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.letter-bcjanegitz.n39","url":null,"abstract":"Since the decade of the 90s when the first works of professor Joseph Wang were published, screen-printed electrodes have been proposed for many objectives. In the first works in Brazil a few years later, some authors proposed electrochemical sensors using graphite from batteries, which provide great results for the determination of several analytes.1 In another interesting work, Professor Lucio Angnes (USP) and collaborators prepared gold electrodes from CD, which presented a thin film of the noble metal.2 They obtained an extremely low-cost electrochemical sensor. After that, this research line gained notoriety in Brazil, and the number of groups and papers has increased considerably. In this regard, we can highlight some researchers that have been working on low-cost and disposable electrochemical sensors, including Lauro Kubota (UNICAMP), Luiz Humberto Marcolino Junior (UFPR), Márcio Fernando Bergamini (UFPR), Ronaldo Censi Faria (UFSCar), Éder Cavalheiro (USP), Osvaldo Novais de Oliveira Junior (USP), Sergio Spínola (USP), Murilo Santiago (CNPEM), Renato Souza Lima (CNPEM), Orlando Fatibello Filho (UFSCar), Wendell Coltro (USP), William Reis (UNICAMP), and Thiago Paixão (USP). The laboratory of Sensors, Nanomedicine, and Nanostructured Materials (LSNano) located at UFSCar Araras has also developed low-cost sensors using recyclable materials and conductive inks with simple preparation. Low-cost electrodes can be prepared with infinite possibilities by using different substrates, such as circuit boards,3 acetate sheets,4 and polyethylene terephthalate (PET) from bottles5 as well as paper6. In the last example, various types of papers have been applied in this area, including cardboard,7 waterproof,6 and adhesives8. Therefore, materials that we use daily can become important devices with great applications. There are many options to produce low-cost electrochemical sensors, including pencil drawing, stencil, laser scribing, and screen-printing techniques.9 The strategy depends on the subject and the materials that have been deposited to be used as conductors. In this context, the screen-printing technique is come from the t-shirt preparation and is an excellent alternative to produce hundreds of sensors in a few minutes. They can be applied by using different electrochemical techniques, such as potentiometry, voltammetry, and electrochemical impedance spectroscopy. For this purpose, low-cost inks, which are made of a polymer and a conductive material, are necessary. Conductive inks can be prepared with water based-polymers,10 nail polish,11 and traditional polymers based on organic solvents12. Otherwise, graphite carbon nanotubes and/or graphene and carbon dots have been used as conductive carbon-based materials.13 Also, metallic nanoparticles such as copper, platinum, and gold can be great alternatives for this intention but can be quite costly.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49334834","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 : 2023-04-03DOI: 10.30744/brjac.2179-3425.ar-93-2022
F. Felix, Matheus Bazzana, L. Assis, Bethânia Mansur, Sara S. Vieira, Z. Magriotis, Leonardo Kumura, A. Saczk
An electrochemical sensor modified with zeolite dealuminated with citric acid was developed for the determination of hydroxyzine in pharmaceutical products during BIA-amperometry experiments. The modified electrochemical sensor was prepared by mixing powdered graphite with zeolite treated with citric acid homogenized with hexane and mineral oil (60:20:20% w/w/w respectively). The developed sensor showed reproducible amperometric responses in a linear range of 1.0x10-6 – 2.0x10-5 mol L-1 in +1,28V (vs. Ag/AgCl). The detection limit and detection limit found were 3.10x10-7 mol L-1 e 1.04x10-6 mol L-1, respectively. The method developed by BIA-amperometry was applied for the determination of the analyte in tablets and commercial syrups and the results found agreement with the nominal values of the commercial samples.
{"title":"Development of an electrochemical sensor modified with dealuminated zeolite with citric acid for hydroxyzine determination by BIA-Amperometry","authors":"F. Felix, Matheus Bazzana, L. Assis, Bethânia Mansur, Sara S. Vieira, Z. Magriotis, Leonardo Kumura, A. Saczk","doi":"10.30744/brjac.2179-3425.ar-93-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-93-2022","url":null,"abstract":"An electrochemical sensor modified with zeolite dealuminated with citric acid was developed for the determination of hydroxyzine in pharmaceutical products during BIA-amperometry experiments. The modified electrochemical sensor was prepared by mixing powdered graphite with zeolite treated with citric acid homogenized with hexane and mineral oil (60:20:20% w/w/w respectively). The developed sensor showed reproducible amperometric responses in a linear range of 1.0x10-6 – 2.0x10-5 mol L-1 in +1,28V (vs. Ag/AgCl). The detection limit and detection limit found were 3.10x10-7 mol L-1 e 1.04x10-6 mol L-1, respectively. The method developed by BIA-amperometry was applied for the determination of the analyte in tablets and commercial syrups and the results found agreement with the nominal values of the commercial samples.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44340837","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 : 2023-03-17DOI: 10.30744/brjac.2179-3425.ar-108-2022
Jessica Selva, M. Bertotti
The fabrication and long-term application of a pH Au microelectrode based on an iridium oxide film are reported. A uniform iridium oxide film with a typical thickness of around 1 µm was coated on the microelectrode surface through a 2-step procedure involving electrodeposition at constant potential and further continuous voltammetric scans. A super-Nernstian slope of around 77 mV per pH unit was found from open circuit potential measurements in a broad pH range (2 to 10) in 0.01 mol L-1 phosphate buffer. It was demonstrated experimentally that the short-term pH precision of the IrOx sensor is ± 0.1 pH. The response stability was maintained in the physiological pH range, and the sensor exhibited excellent reproducibility, long-term stability, and a short response time of < 10 s. The results reported in this work confirmed that iridium oxide showed very promising pH sensing performance and can serve as an electrode material for detecting local pH changes in samples of increased complexity, such as juice fruits, culture medium, synthetic urine, and blood.
{"title":"Iridium Oxides Based Potentiometric Sensor for pH Monitoring in Biological Samples","authors":"Jessica Selva, M. Bertotti","doi":"10.30744/brjac.2179-3425.ar-108-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-108-2022","url":null,"abstract":"The fabrication and long-term application of a pH Au microelectrode based on an iridium oxide film are reported. A uniform iridium oxide film with a typical thickness of around 1 µm was coated on the microelectrode surface through a 2-step procedure involving electrodeposition at constant potential and further continuous voltammetric scans. A super-Nernstian slope of around 77 mV per pH unit was found from open circuit potential measurements in a broad pH range (2 to 10) in 0.01 mol L-1 phosphate buffer. It was demonstrated experimentally that the short-term pH precision of the IrOx sensor is ± 0.1 pH. The response stability was maintained in the physiological pH range, and the sensor exhibited excellent reproducibility, long-term stability, and a short response time of < 10 s. The results reported in this work confirmed that iridium oxide showed very promising pH sensing performance and can serve as an electrode material for detecting local pH changes in samples of increased complexity, such as juice fruits, culture medium, synthetic urine, and blood.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49333634","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 : 2023-03-10DOI: 10.30744/brjac.2179-3425.letter-almeida-cass
Fernando Almeida, Q. Cass
Affinity selection mass spectrometry (AS-MS) has been shown to be a powerful tool for identifying bioactive molecules in synthetic and/or natural libraries. The selection provided by the formation of the target-ligand complex allows the identification of hits irrespective of their functional effect. Moreover, it precludes the use of label, since the binders are identified by their exact mass.1 The binders are determined by an affinity or index ratio calculated through control assays. The target protein can be used in solution or immobilized in a solid support (Figure 1). Both approaches have pros and cons. Unlike most conventional high-throughput screening assays, AS-MS has fewer or no limitations when it comes to target selection. It is important, however, to understand the implications of choosing membrane proteins as targets. Membrane proteins correspond to 42% of all drug targets listed in DrugBank. Moreover, they are likely to be selected as protein targets due to their participation in many disease pathways, acting as ion channels, molecular transporters, solute carriers, receptors, and anchors. One of the bottlenecks in working with membrane proteins comes from the need to use a detergent for solubilization, folding, and structure maintenance. Detergents are usually used above the critical micelle concentration, which can lead to empty micelles and thus to false positive results, caused by nonspecific interactions with the detergent micelles.8 Interference in the ionization of the binders also needs to be examined.
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Pub Date : 2023-03-10DOI: 10.30744/brjac.2179-3425.point-of-view-mvbzanoni
M. Zanoni
How to artificially mimic a natural process as important and complex as photosynthesis in plants? Apart from being essential for life on our planet, the phenomenon of artificial photosynthesis is intriguing because it provides an incredible ability to capture light and energy, subsequently converting it into chemical energy with high-quantum efficiency. As a consequence of increasing economic and environmental interest, research on artificial photosynthesis has increased; an exponential growth has been seen from the 21st century onwards, with mastery of the phenomenon’s mechanisms being a major challenge to stimulate further development of the subject. Since the 20th century, there have been great expectations regarding further advancing the process of artificial photosynthesis due to the clear recognition of its importance for humanity. With increasing problems in the context of climate change and energy shortages, the possibility of using the core concepts of photosynthesis to contribute to advancing our knowledge on the generation of clean energy from water splitting and hydrogen production, and the recycling of CO2 into hydrocarbon compounds and/or fuels with ample added value has become increasingly important.
{"title":"Artificial Photosynthesis Technology: Is it Possible?","authors":"M. Zanoni","doi":"10.30744/brjac.2179-3425.point-of-view-mvbzanoni","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.point-of-view-mvbzanoni","url":null,"abstract":"How to artificially mimic a natural process as important and complex as photosynthesis in plants? Apart from being essential for life on our planet, the phenomenon of artificial photosynthesis is intriguing because it provides an incredible ability to capture light and energy, subsequently converting it into chemical energy with high-quantum efficiency. As a consequence of increasing economic and environmental interest, research on artificial photosynthesis has increased; an exponential growth has been seen from the 21st century onwards, with mastery of the phenomenon’s mechanisms being a major challenge to stimulate further development of the subject. Since the 20th century, there have been great expectations regarding further advancing the process of artificial photosynthesis due to the clear recognition of its importance for humanity. With increasing problems in the context of climate change and energy shortages, the possibility of using the core concepts of photosynthesis to contribute to advancing our knowledge on the generation of clean energy from water splitting and hydrogen production, and the recycling of CO2 into hydrocarbon compounds and/or fuels with ample added value has become increasingly important.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45029722","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 : 2023-03-02DOI: 10.30744/brjac.2179-3425.tn-80-2022
P. Onofre, D. Barros, Gabriela Silva, F. Fonseca, P. Rosa, M. Pedreira, M. Peterlini
Vancomycin hydrochloride is a tricyclic glycopeptide that contains amino acids and sugars. This substance is indicated to treat serious infections caused by Gram-positive bacteria by intravenous infusion. The objective of this study was to develop and validate an analytical methodology by high performance liquid chromatography with ultraviolet detection (HPLC-UV) to determine vancomycin hydrochloride content by assessing the parameters of selectivity, linearity, working range, matrix effect, robustness, precision, and accuracy. The sample used was vancomycin hydrochloride in a vial and analyzes were carried out on HPLC-UV system, with C18 reverse-phase column at 30 °C, pH=4 and diode-array detection (220 nm). The mobile phase was composed of acetonitrile and monobasic ammonium phosphate buffer (8:92 v/v), 1 mL min-1 flow, injection volume of 20 μL and 15 minute of run time. The method has been shown to be selective, free from mobile phase interference, diluent and other substances on vancomycin hydrochloride retention time; the method is linear in the range between 25 and 175 µg mL-1; matrix effect showed parallelism between the lines, thus indicating the absence of interference of the matrix constituents in analysis of the compound of interest; the method was robust with drug variations proportional to the deliberate changes caused by the change in the flow rate of the mobile phase and in the column temperature; the method showed accuracy at 25, 50, and 75 µg mL-1 concentrations, showing satisfactory recovery rate after addition of the standard. The analytical methodology described proved to be simple, fast, safe and was considered valid.
盐酸万古霉素是一种含有氨基酸和糖的三环糖肽。该物质适用于静脉输注治疗革兰氏阳性菌引起的严重感染。本研究的目的是通过评估选择性、线性、工作范围、基质效应、稳健性、精密度和准确性等参数，开发并验证一种通过高效液相色谱紫外检测（HPLC-UV）测定盐酸万古霉素含量的分析方法。所用样品为小瓶中的万古霉素盐酸盐，并在HPLC-UV系统上进行分析，C18反相柱在30°C、pH=4和二极管阵列检测（220nm）下进行。流动相由乙腈和磷酸二氢铵缓冲液（8:92 v/v）组成，流速为1 mL min-1，进样体积为20μL，运行时间为15分钟。该方法已被证明是选择性的，不受流动相干扰，稀释剂等物质对万古霉素盐酸盐的保留时间；该方法在25至175µg mL-1范围内呈线性；基质效应显示出线条之间的平行性，从而表明基质成分在感兴趣化合物的分析中不存在干扰；该方法是稳健的，药物变化与流动相流速和柱温度变化引起的故意变化成比例；该方法在25、50和75µg mL-1浓度下显示出准确度，添加标准品后显示出令人满意的回收率。所描述的分析方法被证明是简单、快速、安全的，并且被认为是有效的。
{"title":"Development and Validation of a High Performance Liquid Chromatography Ultraviolet Detection Method for the Quantitative Determination of Vancomycin Hydrochloride","authors":"P. Onofre, D. Barros, Gabriela Silva, F. Fonseca, P. Rosa, M. Pedreira, M. Peterlini","doi":"10.30744/brjac.2179-3425.tn-80-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.tn-80-2022","url":null,"abstract":"Vancomycin hydrochloride is a tricyclic glycopeptide that contains amino acids and sugars. This substance is indicated to treat serious infections caused by Gram-positive bacteria by intravenous infusion. The objective of this study was to develop and validate an analytical methodology by high performance liquid chromatography with ultraviolet detection (HPLC-UV) to determine vancomycin hydrochloride content by assessing the parameters of selectivity, linearity, working range, matrix effect, robustness, precision, and accuracy. The sample used was vancomycin hydrochloride in a vial and analyzes were carried out on HPLC-UV system, with C18 reverse-phase column at 30 °C, pH=4 and diode-array detection (220 nm). The mobile phase was composed of acetonitrile and monobasic ammonium phosphate buffer (8:92 v/v), 1 mL min-1 flow, injection volume of 20 μL and 15 minute of run time. The method has been shown to be selective, free from mobile phase interference, diluent and other substances on vancomycin hydrochloride retention time; the method is linear in the range between 25 and 175 µg mL-1; matrix effect showed parallelism between the lines, thus indicating the absence of interference of the matrix constituents in analysis of the compound of interest; the method was robust with drug variations proportional to the deliberate changes caused by the change in the flow rate of the mobile phase and in the column temperature; the method showed accuracy at 25, 50, and 75 µg mL-1 concentrations, showing satisfactory recovery rate after addition of the standard. The analytical methodology described proved to be simple, fast, safe and was considered valid.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48061708","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 : 2023-03-02DOI: 10.30744/brjac.2179-3425.ar-135-2022
Luana da Costa, M. Arruda
A methodology for simultaneous hydride forming elements was established with accuracy and precision, and alicable to different generations of the soybean seeds. In fact, a unique condition for As, Se, Sb and Te determination by hydride-generation coupled to ICP-MS was established as the optimized concentrations of HCl at 6 mol/L and sodium tetrahydroborate at 0.3% (m v-1), and the analytical curve prepared containing all four elements ranging from 10 to 100 ng L-1. For checking the accuracy, the NIST SRM 1568a (Rice Flour) material was used, and good recoveries ranging from 71.7 to 126% were found for the hydrides forming elements. After optimizing, the method was alied to different generations of soybean seeds, indicating a low content of As (from 17 to 29 ng kg-1) and Se (from 42 to 50 ng kg-1) in some of these generations, and concentrations below the LOQ for Sb and Te. All evaluations were obtained after analyzing, at least, in triplicates. Although found low concentrations for As and Se, these results are, at least, intriguing, because they not follow a tendency along generations, and they are discussed along the text.
{"title":"Simultaneous Hydride Generation Inductively Coupled Plasma Mass Spectrometry for the Evaluation of Different Generations of Soybean Seeds","authors":"Luana da Costa, M. Arruda","doi":"10.30744/brjac.2179-3425.ar-135-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-135-2022","url":null,"abstract":"A methodology for simultaneous hydride forming elements was established with accuracy and precision, and alicable to different generations of the soybean seeds. In fact, a unique condition for As, Se, Sb and Te determination by hydride-generation coupled to ICP-MS was established as the optimized concentrations of HCl at 6 mol/L and sodium tetrahydroborate at 0.3% (m v-1), and the analytical curve prepared containing all four elements ranging from 10 to 100 ng L-1. For checking the accuracy, the NIST SRM 1568a (Rice Flour) material was used, and good recoveries ranging from 71.7 to 126% were found for the hydrides forming elements. After optimizing, the method was alied to different generations of soybean seeds, indicating a low content of As (from 17 to 29 ng kg-1) and Se (from 42 to 50 ng kg-1) in some of these generations, and concentrations below the LOQ for Sb and Te. All evaluations were obtained after analyzing, at least, in triplicates. Although found low concentrations for As and Se, these results are, at least, intriguing, because they not follow a tendency along generations, and they are discussed along the text.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48202170","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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