Pub Date : 2023-02-10DOI: 10.30744/brjac.2179-3425.ar-121-2022
M. Mesko, R. Pereira, Natalia Bielemann, F. Rondan, D. Novo
The determination of iodine in iodized mineral dietary supplements is considered a challenge, especially in view of the variety in the sample composition and the analyte concentration. Thus, in this work, microwave-induced combustion (MIC) was combined with ion chromatography (IC) and ion-selective electrode potentiometry (ISE) for iodine determination and dose uniformity assays in mineral dietary supplements. Sample masses up to 800 mg were efficiently digested and only a diluted alkaline solution (200 mmol L-1 NH4OH) was necessary to absorb the analyte for further determination step. The final digest was fully compatible with multi-technique detection usually available in routine analysis laboratories. Recoveries ranging from 94% to 106% was achieved and relative standard deviations for repeatability and intermediate precision were always lower than 8%. Limits of quantification were 4 µg g-1 and 10 µg g-1, respectively, by using IC and ISE. The analytical method was applied for iodine determination in mineral dietary supplements from four brands with different iodine dosages (from 100 to 1250 μg g-1, according to the manufacturers) and for uniformity assay evaluation using individual tablets/capsules of mineral dietary supplements. Non-compliance regarding label information for some samples was reported, drawing the attention of supervisory institutions. The analytical strategies presented in the present study can be successfully used in routine analysis of the quality control of mineral dietary supplements.
{"title":"Multi-Techniques for Iodine Determination and Dose Uniformity Assays in Iodized Mineral Dietary Supplements","authors":"M. Mesko, R. Pereira, Natalia Bielemann, F. Rondan, D. Novo","doi":"10.30744/brjac.2179-3425.ar-121-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-121-2022","url":null,"abstract":"The determination of iodine in iodized mineral dietary supplements is considered a challenge, especially in view of the variety in the sample composition and the analyte concentration. Thus, in this work, microwave-induced combustion (MIC) was combined with ion chromatography (IC) and ion-selective electrode potentiometry (ISE) for iodine determination and dose uniformity assays in mineral dietary supplements. Sample masses up to 800 mg were efficiently digested and only a diluted alkaline solution (200 mmol L-1 NH4OH) was necessary to absorb the analyte for further determination step. The final digest was fully compatible with multi-technique detection usually available in routine analysis laboratories. Recoveries ranging from 94% to 106% was achieved and relative standard deviations for repeatability and intermediate precision were always lower than 8%. Limits of quantification were 4 µg g-1 and 10 µg g-1, respectively, by using IC and ISE. The analytical method was applied for iodine determination in mineral dietary supplements from four brands with different iodine dosages (from 100 to 1250 μg g-1, according to the manufacturers) and for uniformity assay evaluation using individual tablets/capsules of mineral dietary supplements. Non-compliance regarding label information for some samples was reported, drawing the attention of supervisory institutions. The analytical strategies presented in the present study can be successfully used in routine analysis of the quality control of mineral dietary supplements.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47310817","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 : 2023-02-03DOI: 10.30744/brjac.2179-3425.tn-94-2022
Graciela Heidrich, V. Neves, N. Stefanello, V. Miron, T. Lopes, Sindy Krzyzaniak, Paola Mello, M. Schetinger, D. Pozebon, V. Dressler
Adult Wistar rats were exposed to lanthanum oxide nanoparticles (La2O3-NPs). Animals were initially treated with single doses of La2O3-NPs suspensions at 5.0, 50, 300 and 2000 mg kg-1 per body weight (bw), which were orally administered. Behavior changes, symptoms of intoxication and mortality were not observed for individuals treated with the La2O3-NPs. However, the histological analysis of different organs of the treated rats revealed that 300 mg kg-1 and 2000 mg kg-1 bw La2O3-NPs caused hepatic lesions. Subsequently, 40 individuals were divided in four groups with 10 individuals in each group and daily treated with water only (control) and with 1.0, 10 and 100 mg kg-1 bw La2O3-NPs. After 30 days, it was observed that the La2O3-NPs did not affect the body weight and organs weight of the animals. The La2O3-NPs also did not change the levels of creatinine, urea, glutamyl transferase (γ-GT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and thiobarbituric acid reactive substances (TBARS) in blood serum. Neurotoxicity, evaluated by the acetylcholinesterase (AChE) activity, was not observed as well. An increase of reactive oxygen species (ROS) was found in kidney of rats treated with 100 mg kg-1 bw La2O3-NPs. Conversely, protein oxidation decreased in the liver of those animals. The catalase (CAT) activity was not affected by La2O3-NPs and that of superoxide dismutase (SOD) was in the liver of animals treated with 10 mg kg-1 bw La2O3-NPs. Lanthanum was determined in organs and blood of the treated animals. The element was not detected in the blood but was in the organs, in higher concentration in liver, kidneys, and heart. Lanthanum present in the form of NPs or as free ion could not be detected. As such, it is worth investigating possible transformation of La2O3-NPs in the organism, their elimination routes, and effects of longer exposure times.
{"title":"Lanthanum Oxide Nanoparticles Distribution in Wistar Rats after Oral Exposure and Respective Effects","authors":"Graciela Heidrich, V. Neves, N. Stefanello, V. Miron, T. Lopes, Sindy Krzyzaniak, Paola Mello, M. Schetinger, D. Pozebon, V. Dressler","doi":"10.30744/brjac.2179-3425.tn-94-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.tn-94-2022","url":null,"abstract":"Adult Wistar rats were exposed to lanthanum oxide nanoparticles (La2O3-NPs). Animals were initially treated with single doses of La2O3-NPs suspensions at 5.0, 50, 300 and 2000 mg kg-1 per body weight (bw), which were orally administered. Behavior changes, symptoms of intoxication and mortality were not observed for individuals treated with the La2O3-NPs. However, the histological analysis of different organs of the treated rats revealed that 300 mg kg-1 and 2000 mg kg-1 bw La2O3-NPs caused hepatic lesions. Subsequently, 40 individuals were divided in four groups with 10 individuals in each group and daily treated with water only (control) and with 1.0, 10 and 100 mg kg-1 bw La2O3-NPs. After 30 days, it was observed that the La2O3-NPs did not affect the body weight and organs weight of the animals. The La2O3-NPs also did not change the levels of creatinine, urea, glutamyl transferase (γ-GT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and thiobarbituric acid reactive substances (TBARS) in blood serum. Neurotoxicity, evaluated by the acetylcholinesterase (AChE) activity, was not observed as well. An increase of reactive oxygen species (ROS) was found in kidney of rats treated with 100 mg kg-1 bw La2O3-NPs. Conversely, protein oxidation decreased in the liver of those animals. The catalase (CAT) activity was not affected by La2O3-NPs and that of superoxide dismutase (SOD) was in the liver of animals treated with 10 mg kg-1 bw La2O3-NPs. Lanthanum was determined in organs and blood of the treated animals. The element was not detected in the blood but was in the organs, in higher concentration in liver, kidneys, and heart. Lanthanum present in the form of NPs or as free ion could not be detected. As such, it is worth investigating possible transformation of La2O3-NPs in the organism, their elimination routes, and effects of longer exposure times.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45727229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-19DOI: 10.30744/brjac.2179-3425.ar-125-2022
Florencia Tissot, Maite Cuadrado, J. Santander, J. Torres, I. Machado
Moringa stenopetala is a tropical tree from the Moringaceae family, native to north-east Africa, that has widespread to many countries. It is highly valued for the associated nutritional and medicinal properties. The nutritional value of South American Moringa stenopetala was assessed in this work, giving some deeper insight into the expected biological accessibility of the main nutrients present in raw leaves and prepared infusions. Metal ions were determined by FAAS; L-ascorbic acid, leucine, and tryptophan by LC-DAD; rutin, isoquercitrin and neochlorogenic acid by LC-ESI-MS/MS. Metal ions content in analyzed specimens was in the same order of previously reported data, except for lower values for iron, probably associated to the different soil composition. Tested amino acids were also found in the previously reported range, while higher contents of L-ascorbic acid, rutin and neochlorogenic acid were determined. Interestingly, transfer factors to infusions resulted especially low for magnesium, calcium, iron, and L-ascorbic acid, indicating that the way of consumption exerts a strong influence on the nutritional value of the vegetal material. Chemical speciation modeling experiments to predict bioaccessibility showed that sodium, potassium, magnesium, and calcium ions to be predominantly free. On the other hand, the micronutrients are predicted to be partly associated to polyphenolic compounds. Finally, the antioxidant activity was studied both in the vegetal material and the prepared infusions by the ORAC assay, both showing relevant antioxidant activity probably associated to the high rutin content. This biomolecule, together with other polyphenolic compounds present, are expected to partially retain metal ions in solution, also contributing to the antioxidant beneficial properties of Moringa stenopetala.
{"title":"Nutritional and Antioxidant Properties of South American Moringa stenopetala","authors":"Florencia Tissot, Maite Cuadrado, J. Santander, J. Torres, I. Machado","doi":"10.30744/brjac.2179-3425.ar-125-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-125-2022","url":null,"abstract":"Moringa stenopetala is a tropical tree from the Moringaceae family, native to north-east Africa, that has widespread to many countries. It is highly valued for the associated nutritional and medicinal properties. The nutritional value of South American Moringa stenopetala was assessed in this work, giving some deeper insight into the expected biological accessibility of the main nutrients present in raw leaves and prepared infusions. Metal ions were determined by FAAS; L-ascorbic acid, leucine, and tryptophan by LC-DAD; rutin, isoquercitrin and neochlorogenic acid by LC-ESI-MS/MS. Metal ions content in analyzed specimens was in the same order of previously reported data, except for lower values for iron, probably associated to the different soil composition. Tested amino acids were also found in the previously reported range, while higher contents of L-ascorbic acid, rutin and neochlorogenic acid were determined. Interestingly, transfer factors to infusions resulted especially low for magnesium, calcium, iron, and L-ascorbic acid, indicating that the way of consumption exerts a strong influence on the nutritional value of the vegetal material. Chemical speciation modeling experiments to predict bioaccessibility showed that sodium, potassium, magnesium, and calcium ions to be predominantly free. On the other hand, the micronutrients are predicted to be partly associated to polyphenolic compounds. Finally, the antioxidant activity was studied both in the vegetal material and the prepared infusions by the ORAC assay, both showing relevant antioxidant activity probably associated to the high rutin content. This biomolecule, together with other polyphenolic compounds present, are expected to partially retain metal ions in solution, also contributing to the antioxidant beneficial properties of Moringa stenopetala.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44385739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.30744/brjac.2179-3425.letter-hudsoncarvalho.n38
H. Carvalho
Elemental chemical images reveal how the elements are distributed in a sample. While it may sound useless for a homogeneous solution, it is crucial for understanding properties of heterogeneous systems, such as a rock1, a cereal grain2, or a painting3. In such cases, revealing the chemical composition of parts of the sample might reveal the distribution of minerals, nutrients, or toxic elements. All strategies for measuring the spatial distribution of elements require a probe, whose size will define the lateral resolution of the image, and a detection system. Some techniques are destructive while others preserve the specimen; this latter feature is of special importance for rare and mass-limited samples or in the case of in vivo analysis. Laser ablation coupled to mass spectrometry or optical emission spectrometry, laser induced break down spectrometry, and microprobe X-ray fluorescence spectrometry are some of the most common laboratory techniques employed in chemical imaging.
{"title":"Past, Present, and Future of X-ray Fluorescence Chemical Imaging","authors":"H. Carvalho","doi":"10.30744/brjac.2179-3425.letter-hudsoncarvalho.n38","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.letter-hudsoncarvalho.n38","url":null,"abstract":"Elemental chemical images reveal how the elements are distributed in a sample. While it may sound useless for a homogeneous solution, it is crucial for understanding properties of heterogeneous systems, such as a rock1, a cereal grain2, or a painting3. In such cases, revealing the chemical composition of parts of the sample might reveal the distribution of minerals, nutrients, or toxic elements. All strategies for measuring the spatial distribution of elements require a probe, whose size will define the lateral resolution of the image, and a detection system. Some techniques are destructive while others preserve the specimen; this latter feature is of special importance for rare and mass-limited samples or in the case of in vivo analysis. Laser ablation coupled to mass spectrometry or optical emission spectrometry, laser induced break down spectrometry, and microprobe X-ray fluorescence spectrometry are some of the most common laboratory techniques employed in chemical imaging.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46041127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.30744/brjac.2179-3425.editorial.imaging
R. Augusti, V. Dressler
Over the past few years, chemical imaging technologies have experienced a dramatic increase in the number and diversity of applications. This is mainly due to the ability of such technologies to provide the spatial distribution of the various components of a sample. The spatial distribution of a specific chemical component in a given sample constitutes a precious piece of information. This is the base of several applications in different areas such as plant physiology, food safety, biomedical diagnosis, forensic analysis, pharmaceutical monitoring, cell analysis, and defense, among many others. Thus, this BrJAC special edition entitled “Chemical Imaging” intends to provide an overview of these new technologies and their use in the most diverse areas of knowledge. All the works presented in this special issue were carried out by research groups based in laboratories of universities in South America. Despite the enormous difficulties facing the development of science in the region, the manuscripts published in this special issue put in evidence the excellent quality of the science produced once they are at the frontier of knowledge.
{"title":"Novel Applications of Chemical Imaging, an Outstanding Technology","authors":"R. Augusti, V. Dressler","doi":"10.30744/brjac.2179-3425.editorial.imaging","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.editorial.imaging","url":null,"abstract":"Over the past few years, chemical imaging technologies have experienced a dramatic increase in the number and diversity of applications. This is mainly due to the ability of such technologies to provide the spatial distribution of the various components of a sample. The spatial distribution of a specific chemical component in a given sample constitutes a precious piece of information. This is the base of several applications in different areas such as plant physiology, food safety, biomedical diagnosis, forensic analysis, pharmaceutical monitoring, cell analysis, and defense, among many others. Thus, this BrJAC special edition entitled “Chemical Imaging” intends to provide an overview of these new technologies and their use in the most diverse areas of knowledge. All the works presented in this special issue were carried out by research groups based in laboratories of universities in South America. Despite the enormous difficulties facing the development of science in the region, the manuscripts published in this special issue put in evidence the excellent quality of the science produced once they are at the frontier of knowledge.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48490590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.30744/brjac.2179-3425.interview.dressler
V. Dressler
Valderi Luiz Dressler holds a chemistry degree (1992) and a master’s in chemistry (1994) from the Federal University of Santa Maria (UFSM), RS, Brazil, a PhD in chemistry (1999) from the Federal University of Santa Catarina, SC, Brazil and post-doctorates from Forschungszentrum Julich GmbH, Germany (2007 and 2010). Currently, he is a full professor and coordinator of the industrial chemistry and bachelor's chemistry degree courses at the UFSM. Dr. Dressler’s research activities mainly include trace analysis and environmental chemistry, involving the techniques of atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), flow injection analysis (FIA), electrothermal vaporization (ETV) and laser ablation (LA). Furthermore, he performs chemical speciation analysis studies involving hyphenated techniques such as liquid and gas chromatography coupled to ICP-MS and also FIA systems coupled to AAS.
{"title":"Professor Valderi Dressler, a great admirer of young Brazilian scientists, kindly granted BrJAC an interview","authors":"V. Dressler","doi":"10.30744/brjac.2179-3425.interview.dressler","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.interview.dressler","url":null,"abstract":"Valderi Luiz Dressler holds a chemistry degree (1992) and a master’s in chemistry (1994) from the Federal University of Santa Maria (UFSM), RS, Brazil, a PhD in chemistry (1999) from the Federal University of Santa Catarina, SC, Brazil and post-doctorates from Forschungszentrum Julich GmbH, Germany (2007 and 2010). Currently, he is a full professor and coordinator of the industrial chemistry and bachelor's chemistry degree courses at the UFSM. Dr. Dressler’s research activities mainly include trace analysis and environmental chemistry, involving the techniques of atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), flow injection analysis (FIA), electrothermal vaporization (ETV) and laser ablation (LA). Furthermore, he performs chemical speciation analysis studies involving hyphenated techniques such as liquid and gas chromatography coupled to ICP-MS and also FIA systems coupled to AAS.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49669658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.30744/brjac.2179-3425.interview.augusti
R. Augusti
Rodinei Augusti holds a degree in chemistry (1986), a master’s degree in chemistry (1990), and a doctorate in chemistry (1993), all from the University of Campinas (UNICAMP), SP, Brazil. Currently, he is a full professor in the Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil. He conducts research on the application of mass spectrometry in several areas, such as monitoring reactions of environmental interest and quality control of alcoholic beverages. Prof. Augusti is an advisor to the following journals: Rapid Communications in Mass Spectrometry, Journal of Mass Spectrometry, Analytical Chemistry, Inorganic Chemistry, Journal of the Brazilian Chemical Society, Analyst (London), Journal of the American Society for Mass Spectrometry, and Quimica Nova.
{"title":"Professor Rodinei Augusti, an enthusiast for the progress of chemistry in Brazil, kindly spoke to BrJAC","authors":"R. Augusti","doi":"10.30744/brjac.2179-3425.interview.augusti","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.interview.augusti","url":null,"abstract":"Rodinei Augusti holds a degree in chemistry (1986), a master’s degree in chemistry (1990), and a doctorate in chemistry (1993), all from the University of Campinas (UNICAMP), SP, Brazil. Currently, he is a full professor in the Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil. He conducts research on the application of mass spectrometry in several areas, such as monitoring reactions of environmental interest and quality control of alcoholic beverages. Prof. Augusti is an advisor to the following journals: Rapid Communications in Mass Spectrometry, Journal of Mass Spectrometry, Analytical Chemistry, Inorganic Chemistry, Journal of the Brazilian Chemical Society, Analyst (London), Journal of the American Society for Mass Spectrometry, and Quimica Nova.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45113559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.30744/brjac.2179-3425.point-of-view-asussulini.n38
Alessandra Sussulini
Chemical images can be described as distribution maps that correlate the chemical information of an element or molecule, such as mass-to-charge ratio (m/z) or wavelength, with its intensity and/or concentration in a given sample. These images are usually obtained by mass spectrometry (MS) or optical spectroscopy techniques, where hundreds or thousands of spectra are initially acquired and dedicated image processing software is employed to construct and edit the final pictures, as well as selecting and annotating regions of interest in a sample, performing calibration procedures, etc. Mass spectrometry imaging (preferably abbreviated as MSI, to distinguish it from ion mobility spectrometry – IMS) is currently the most employed chemical imaging strategy, as can be noticed in the most recently published papers. Depending on the selected ionization technique, molecular or elemental images can be acquired. For molecular MSI, the classical matrix-assisted laser desorption/ionization (MALDI) is generally applied for imaging lipids, peptides and proteins, and the ambient ionization technique desorption electrospray ionization (DESI) is commonly applied for visualizing lipid distribution. In terms of elemental MSI, laser ablation inductively coupled plasma (LA-ICP) is undoubtedly the technique of choice, although nano-secondary ion mass spectrometry (nanoSIMS) can also be applied. Considering optical spectroscopy, the main techniques used nowadays are Raman and near-infrared radiation – NIR – spectroscopy for molecular imaging, and Synchrotron radiation X-ray fluorescence – SRXRF – and laser-induced breakdown spectroscopy – LIBS – for elemental imaging. Amongst these techniques, the best spatial resolutions are generally achieved by SRXRF (elemental imaging) and Raman spectroscopy (molecular imaging). Analytical chemistry advances in chemical imaging allow the acquisition of images with high spatial resolution, which is particularly interesting when studying specific regions or cell structures in a biological sample. For instance, in a Parkinson’s disease model, LA-ICP-MS images with good spatial resolution make the distinction of specific mouse brain regions possible and, consequently, the association of metal ion concentrations to each region,1 which is a relevant result considering micro-local metal speciation in neurodegenerative diseases. Nevertheless, there are some drawbacks in chemical imaging that demand further analytical development, such as the long analysis time and the lack of certified reference materials for quantitative analysis and method validation, as well as open-source software with advanced multivariate statistical analysis tools. Another obstacle to overcome concerns the integration of elemental and molecular imaging results. Since 2009, when one of the first review articles regarding the combination of these imaging approaches in a synergistic way was proposed by Becker and Jakubowski,2 until more recently described in reviews fro
{"title":"Chemical Imaging – Is an Image Always Worth a Thousand Spectra?","authors":"Alessandra Sussulini","doi":"10.30744/brjac.2179-3425.point-of-view-asussulini.n38","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.point-of-view-asussulini.n38","url":null,"abstract":"Chemical images can be described as distribution maps that correlate the chemical information of an element or molecule, such as mass-to-charge ratio (m/z) or wavelength, with its intensity and/or concentration in a given sample. These images are usually obtained by mass spectrometry (MS) or optical spectroscopy techniques, where hundreds or thousands of spectra are initially acquired and dedicated image processing software is employed to construct and edit the final pictures, as well as selecting and annotating regions of interest in a sample, performing calibration procedures, etc. Mass spectrometry imaging (preferably abbreviated as MSI, to distinguish it from ion mobility spectrometry – IMS) is currently the most employed chemical imaging strategy, as can be noticed in the most recently published papers. Depending on the selected ionization technique, molecular or elemental images can be acquired. For molecular MSI, the classical matrix-assisted laser desorption/ionization (MALDI) is generally applied for imaging lipids, peptides and proteins, and the ambient ionization technique desorption electrospray ionization (DESI) is commonly applied for visualizing lipid distribution. In terms of elemental MSI, laser ablation inductively coupled plasma (LA-ICP) is undoubtedly the technique of choice, although nano-secondary ion mass spectrometry (nanoSIMS) can also be applied. Considering optical spectroscopy, the main techniques used nowadays are Raman and near-infrared radiation – NIR – spectroscopy for molecular imaging, and Synchrotron radiation X-ray fluorescence – SRXRF – and laser-induced breakdown spectroscopy – LIBS – for elemental imaging. Amongst these techniques, the best spatial resolutions are generally achieved by SRXRF (elemental imaging) and Raman spectroscopy (molecular imaging). Analytical chemistry advances in chemical imaging allow the acquisition of images with high spatial resolution, which is particularly interesting when studying specific regions or cell structures in a biological sample. For instance, in a Parkinson’s disease model, LA-ICP-MS images with good spatial resolution make the distinction of specific mouse brain regions possible and, consequently, the association of metal ion concentrations to each region,1 which is a relevant result considering micro-local metal speciation in neurodegenerative diseases. Nevertheless, there are some drawbacks in chemical imaging that demand further analytical development, such as the long analysis time and the lack of certified reference materials for quantitative analysis and method validation, as well as open-source software with advanced multivariate statistical analysis tools. Another obstacle to overcome concerns the integration of elemental and molecular imaging results. Since 2009, when one of the first review articles regarding the combination of these imaging approaches in a synergistic way was proposed by Becker and Jakubowski,2 until more recently described in reviews fro","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42047307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-30DOI: 10.30744/brjac.2179-3425.ar-88-2022
Wilson do Nascimento Filho, M. Cidade, F. Panero, O. Smiderle
In this article, digital image processing and analysis (DIPA) combined with chemometric methods, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to discriminate sesame seeds through their digitized images. For this purpose, four groups of seeds were used: BRS Anahí and BRS Seda cultivars, a lineage and a commercial sample. The images were scanned using an HP officejet 7610 scanner and, for extraction of the red-green-blue channels and colorimetric profile, the ImageJ software was used. The DIPA combined with chemometric methods allowed us to discriminate the four groups of sesame seeds efficiently, and a minimum accumulated variance of 89.03% of the total variance was obtained. The trends observed via the PCA were confirmed through the dendrograms obtained using the HCA. The results achieved in this work indicate that the proposed methodology can be a simple analytical alternative for the non-destructive phenotypic discrimination of seeds, with their color as an attribute.
{"title":"Application of Digital Imaging Allied to Chemometrics in the Use of Non-destructive Phenotyping of Sesame Seeds","authors":"Wilson do Nascimento Filho, M. Cidade, F. Panero, O. Smiderle","doi":"10.30744/brjac.2179-3425.ar-88-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-88-2022","url":null,"abstract":"In this article, digital image processing and analysis (DIPA) combined with chemometric methods, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to discriminate sesame seeds through their digitized images. For this purpose, four groups of seeds were used: BRS Anahí and BRS Seda cultivars, a lineage and a commercial sample. The images were scanned using an HP officejet 7610 scanner and, for extraction of the red-green-blue channels and colorimetric profile, the ImageJ software was used. The DIPA combined with chemometric methods allowed us to discriminate the four groups of sesame seeds efficiently, and a minimum accumulated variance of 89.03% of the total variance was obtained. The trends observed via the PCA were confirmed through the dendrograms obtained using the HCA. The results achieved in this work indicate that the proposed methodology can be a simple analytical alternative for the non-destructive phenotypic discrimination of seeds, with their color as an attribute.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44862043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-18DOI: 10.30744/brjac.2179-3425.ar-68-2022
Antonio Nichele, João dos Santos
Latex (acrylic resin) produced by emulsion polymerization usually contains variable amounts of residual volatiles (free monomers). Depending on the chemical nature of the monomer, even if these compounds are present in smaller quantities than other volatiles, they can make the latex exude a strong odor and offer toxicity, as with ethyl acrylate, which may make it unfeasible for the consumer to apply the latex. In the present study, a quantitative chromatographic method using gas chromatography with a flame ionization detector (GC-FID) for industrial laboratory determination was investigated. Free ethyl acrylate monomer at a concentration level of 0.010% w/w in a resin-type latex was determined. This method showed selectivity for ethyl acrylate versus other volatiles in the sample, linearity with a coefficient of determination greater than 0.99, limits of detection and quantification of 0.001 and 0.003% w/w, respectively, accuracy and precision with recoveries above 85% and coefficients of variation below 10%. The robustness parameter demonstrated with a Pareto chart shows that the chromatographic parameters of the split ratio, injection volume and temperature impact the method performance.
{"title":"Analytical Method for Residual Monomer Ethyl Acrylate Determination in Commercial Latex Resin using Gas Chromatography with Flame Ionization Detection","authors":"Antonio Nichele, João dos Santos","doi":"10.30744/brjac.2179-3425.ar-68-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-68-2022","url":null,"abstract":"Latex (acrylic resin) produced by emulsion polymerization usually contains variable amounts of residual volatiles (free monomers). Depending on the chemical nature of the monomer, even if these compounds are present in smaller quantities than other volatiles, they can make the latex exude a strong odor and offer toxicity, as with ethyl acrylate, which may make it unfeasible for the consumer to apply the latex. In the present study, a quantitative chromatographic method using gas chromatography with a flame ionization detector (GC-FID) for industrial laboratory determination was investigated. Free ethyl acrylate monomer at a concentration level of 0.010% w/w in a resin-type latex was determined. This method showed selectivity for ethyl acrylate versus other volatiles in the sample, linearity with a coefficient of determination greater than 0.99, limits of detection and quantification of 0.001 and 0.003% w/w, respectively, accuracy and precision with recoveries above 85% and coefficients of variation below 10%. The robustness parameter demonstrated with a Pareto chart shows that the chromatographic parameters of the split ratio, injection volume and temperature impact the method performance.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43899941","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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