Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230026
B. Porto, I. Faria, Jéssica Cordeiro Queiroz de Souza, Olívia Moreira, M. D. da Gama, M. D. de Oliveira
Ruminant milk is the lead source of conjugated linoleic acid (CLA) in the human diet, with cis-9, trans-11 CLA being the major among all. Small amounts of trans-10, cis-12 CLA are also found in synthetic supplements. Since both isomers are biologically active with potential health benefits, there is great interest in quantifying them for quality control routines. An alternative method for the analysis of the aforementioned CLAs by fast gas chromatography (GC) is discussed in the present study. The fatty acid methyl ester mixture obtained by alkaline catalysis was injected into a GC equipped with a flame ionization detector (FID) and fitted with an ionic liquid SLB-IL111 chromatographic column (15 m × 0.10 mm × 0.08 µm). Separation was achieved in less than 5 min using a 168 °C isotherm run. Both CLA isomers were quantified by using of single point standard addition statistical approach. Results were contested to those obtained using the recommended 100 m long CP-Sil88 capillary column and none evidence of significant differences was found within 95% confidence interval. Therefore, the proposed method could be valuable to focused regulatory routines of large numbers of samples with greater analytical frequency.
反刍动物奶是人类饮食中共轭亚油酸(CLA)的主要来源，其中顺式-9、反式-11是共轭亚油酸的主要来源。在合成补充剂中也发现了少量的反式-10和顺式-12 CLA。由于这两种异构体都具有生物活性，具有潜在的健康益处，因此对它们进行量化以进行质量控制程序非常有兴趣。本研究讨论了快速气相色谱法(GC)分析上述CLAs的替代方法。将碱催化得到的脂肪酸甲酯混合物注入配备火焰电离检测器(FID)的气相色谱中，并安装离子液体SLB-IL111色谱柱(15 m × 0.10 mm × 0.08µm)。使用168°C等温运行在不到5分钟的时间内实现分离。两种CLA异构体均采用单点标准加法统计方法进行定量分析。结果与使用推荐的100 m CP-Sil88毛细管柱获得的结果存在争议，在95%置信区间内没有发现显著差异的证据。因此，所提出的方法可用于分析频率较高的大量样品的集中监管程序。
{"title":"RAPID METHOD FOR SIMULTANEOUS DETERMINATION OF CIS-9, TRANS-11 AND TRANS-10, CIS-12 CONJUGATED LINOLEIC ACID ISOMERS IN MILK BY GC-FID","authors":"B. Porto, I. Faria, Jéssica Cordeiro Queiroz de Souza, Olívia Moreira, M. D. da Gama, M. D. de Oliveira","doi":"10.21577/0100-4042.20230026","DOIUrl":"https://doi.org/10.21577/0100-4042.20230026","url":null,"abstract":"Ruminant milk is the lead source of conjugated linoleic acid (CLA) in the human diet, with cis-9, trans-11 CLA being the major among all. Small amounts of trans-10, cis-12 CLA are also found in synthetic supplements. Since both isomers are biologically active with potential health benefits, there is great interest in quantifying them for quality control routines. An alternative method for the analysis of the aforementioned CLAs by fast gas chromatography (GC) is discussed in the present study. The fatty acid methyl ester mixture obtained by alkaline catalysis was injected into a GC equipped with a flame ionization detector (FID) and fitted with an ionic liquid SLB-IL111 chromatographic column (15 m × 0.10 mm × 0.08 µm). Separation was achieved in less than 5 min using a 168 °C isotherm run. Both CLA isomers were quantified by using of single point standard addition statistical approach. Results were contested to those obtained using the recommended 100 m long CP-Sil88 capillary column and none evidence of significant differences was found within 95% confidence interval. Therefore, the proposed method could be valuable to focused regulatory routines of large numbers of samples with greater analytical frequency.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230042
WASTE MANAGEMENT IN THE LABORATORIES OF THE UNIVERSITY OF ÉVORA (2007-2021). Waste generated in university laboratories is an important component of university waste management, especially regarding their hazardousness and, also, the cost involved in their forwarding. To make a good management of this waste, it is essential to know the amount generated and the composition. However, this type of information remains scarce. In this work, waste from the laboratories of the University of Évora (Portugal) was surveyed from 2007 to 2021, using existing records. In the 15 years under analysis, the laboratories of the University of Évora generated about 61 tonnes of waste, 88% of which were hazardous and 66% were in the liquid state. In addition, only 3% of this waste was subjected to recovery operations. Moreover, the COVID-19 pandemic contributed to a double increase in hospital waste generated and to a substantially decreased of hazardous liquid waste from the laboratory activity, especially in the first year of the pandemic. In 2021, the second year of the pandemic, there was a “return to normality”, reaching the highest value of waste generated in the laboratories, of 8.6 tonnes. Finally, possible solutions for improving laboratory waste management were also discussed.
{"title":"GESTÃO DE RESÍDUOS NOS LABORATÓRIOS DA UNIVERSIDADE DE ÉVORA (2007-2021)","authors":"","doi":"10.21577/0100-4042.20230042","DOIUrl":"https://doi.org/10.21577/0100-4042.20230042","url":null,"abstract":"WASTE MANAGEMENT IN THE LABORATORIES OF THE UNIVERSITY OF ÉVORA (2007-2021). Waste generated in university laboratories is an important component of university waste management, especially regarding their hazardousness and, also, the cost involved in their forwarding. To make a good management of this waste, it is essential to know the amount generated and the composition. However, this type of information remains scarce. In this work, waste from the laboratories of the University of Évora (Portugal) was surveyed from 2007 to 2021, using existing records. In the 15 years under analysis, the laboratories of the University of Évora generated about 61 tonnes of waste, 88% of which were hazardous and 66% were in the liquid state. In addition, only 3% of this waste was subjected to recovery operations. Moreover, the COVID-19 pandemic contributed to a double increase in hospital waste generated and to a substantially decreased of hazardous liquid waste from the laboratory activity, especially in the first year of the pandemic. In 2021, the second year of the pandemic, there was a “return to normality”, reaching the highest value of waste generated in the laboratories, of 8.6 tonnes. Finally, possible solutions for improving laboratory waste management were also discussed.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230043
Watsaka Siriangkhawut, Kraingkrai Ponhong, P. Chantiratikul, Parita Mayotha
Stripping analysis was proposed for the voltammetric determination of trace cadmium and lead in local rice wine alcoholic beverages. A bismuth-antimony film electrode (Bi-SbFE) was employed for accumulative preconcentration of trace metals by adding 4 mg L-1 of bismuth and 1 mg L-1 of antimony directly to the sample solution and simultaneously depositing bismuth, antimony, and trace cadmium and lead target metals on the glassy carbon electrode by applying a fixed potential of –1.1 V versus the Ag/AgCl reference electrode for 300 s. Pre-treatment parameters for mineralization of the sample were optimized using the wet acid digestion procedure. Under the optimum conditions, linear calibration graphs ranging 20-200 µg L-1 for Cd and Pb were obtained with detection limits of 0.22 and 0.62 µg L-1 and limits of quantitation 0.73 and 2.07 µg L-1, respectively. Reproducibility values for seven replicate analyses of 50 µg L-1 Cd and Pb were 3.6 and 3.3%, respectively. The developed method was successful for Cd and Pb analyses in Thai rice wine samples and results were validated by the flame atomic absorption spectrometric method. Most samples were not contaminated with Cd and Pb. The amount of Cd contaminants in only one of rice wine sample was still lower than the maximum permitted level of Cd in wine.
{"title":"BISMUTH-ANTIMONY FILM ELECTRODE FOR STRIPPING VOLTAMMETRIC DETERMINATION OF TRACE CADMIUM AND LEAD IN THAI RICE WINE","authors":"Watsaka Siriangkhawut, Kraingkrai Ponhong, P. Chantiratikul, Parita Mayotha","doi":"10.21577/0100-4042.20230043","DOIUrl":"https://doi.org/10.21577/0100-4042.20230043","url":null,"abstract":"Stripping analysis was proposed for the voltammetric determination of trace cadmium and lead in local rice wine alcoholic beverages. A bismuth-antimony film electrode (Bi-SbFE) was employed for accumulative preconcentration of trace metals by adding 4 mg L-1 of bismuth and 1 mg L-1 of antimony directly to the sample solution and simultaneously depositing bismuth, antimony, and trace cadmium and lead target metals on the glassy carbon electrode by applying a fixed potential of –1.1 V versus the Ag/AgCl reference electrode for 300 s. Pre-treatment parameters for mineralization of the sample were optimized using the wet acid digestion procedure. Under the optimum conditions, linear calibration graphs ranging 20-200 µg L-1 for Cd and Pb were obtained with detection limits of 0.22 and 0.62 µg L-1 and limits of quantitation 0.73 and 2.07 µg L-1, respectively. Reproducibility values for seven replicate analyses of 50 µg L-1 Cd and Pb were 3.6 and 3.3%, respectively. The developed method was successful for Cd and Pb analyses in Thai rice wine samples and results were validated by the flame atomic absorption spectrometric method. Most samples were not contaminated with Cd and Pb. The amount of Cd contaminants in only one of rice wine sample was still lower than the maximum permitted level of Cd in wine.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230030
Dennis Ferreira, Leticia Rodrigues, Fabiola Pereira, Edenir Pereira‑Filho
PRINCIPAL COMPONENT ANALYSIS (PCA) FOR CHEMICAL DATA EVALUATION AND HEAT MAPS PREPARATION: A TUTORIAL. This tutorial shows a step-by-step guide on handling big datasets using principal component analysis (PCA). A dataset of chemical elements, concentration, emission spectrum, and energy-dispersive X-ray fluorescence (EDXRF) of e-waste were used as examples. Five routines were proposed to apply data processing and PCA calculation focusing data from laser-induced breakdown spectroscopy (LIBS), EDXRF, and heat maps preparation. These routines can be used in various softwares such as MatLab, Octave, R, and Python. PCA was applied in three examples; the first was for concentrations, and the other two were for spectra. An example of heat maps assembling a hyperspectral image of a printed circuit was also described. In addition, a playlist was created on YouTube using the available examples. Therefore, with this tutorial, it may be possible to learn how to deal with a large volume of data by applying PCA. The authors hope to contribute to those researching in the area.
{"title":"PRINCIPAL COMPONENT ANALYSIS (PCA) PARA A AVALIAÇÃO DE DADOS QUÍMICOS E GERAÇÃO DE HEAT MAPS: UM TUTORIAL","authors":"Dennis Ferreira, Leticia Rodrigues, Fabiola Pereira, Edenir Pereira‑Filho","doi":"10.21577/0100-4042.20230030","DOIUrl":"https://doi.org/10.21577/0100-4042.20230030","url":null,"abstract":"PRINCIPAL COMPONENT ANALYSIS (PCA) FOR CHEMICAL DATA EVALUATION AND HEAT MAPS PREPARATION: A TUTORIAL. This tutorial shows a step-by-step guide on handling big datasets using principal component analysis (PCA). A dataset of chemical elements, concentration, emission spectrum, and energy-dispersive X-ray fluorescence (EDXRF) of e-waste were used as examples. Five routines were proposed to apply data processing and PCA calculation focusing data from laser-induced breakdown spectroscopy (LIBS), EDXRF, and heat maps preparation. These routines can be used in various softwares such as MatLab, Octave, R, and Python. PCA was applied in three examples; the first was for concentrations, and the other two were for spectra. An example of heat maps assembling a hyperspectral image of a printed circuit was also described. In addition, a playlist was created on YouTube using the available examples. Therefore, with this tutorial, it may be possible to learn how to deal with a large volume of data by applying PCA. The authors hope to contribute to those researching in the area.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230036
Isabela Santos, Dalva de Faria
ELECTRONIC TRANSITIONS IN α-FE2O3: THEORETICAL MODELS AND LIMITATIONS. Addressing electronic transitions of hematite (α-Fe2O3) is still considered a topic in active debate, even though it is one of the most widely used compounds from ancient times to the present and also one of the most extensively investigated iron oxides. In this review, a general analysis of the approaches and theoretical models which had been used to explain the electronic absorption spectrum of α-Fe2O3, from the first proposal presented by Tandon and Gupta (1970) to the more recent results obtained by quantum mechanical calculations, is presented. The analysis of the already published studies is made pointing out the main factors that must be considered to allow a more reliable understanding of the UV-Vis-NIR spectra of α-Fe2O3. Furthermore, controversies in the calculated results are discussed, analysing the suitability of each of the approaches used. Reasons for differences observed in the experimental data reported in the literature are also discussed.
{"title":"TRANSIÇÕES ELETRÔNICAS EM α-Fe2O3: MODELOS TEÓRICOS E LIMITAÇÕES","authors":"Isabela Santos, Dalva de Faria","doi":"10.21577/0100-4042.20230036","DOIUrl":"https://doi.org/10.21577/0100-4042.20230036","url":null,"abstract":"ELECTRONIC TRANSITIONS IN α-FE2O3: THEORETICAL MODELS AND LIMITATIONS. Addressing electronic transitions of hematite (α-Fe2O3) is still considered a topic in active debate, even though it is one of the most widely used compounds from ancient times to the present and also one of the most extensively investigated iron oxides. In this review, a general analysis of the approaches and theoretical models which had been used to explain the electronic absorption spectrum of α-Fe2O3, from the first proposal presented by Tandon and Gupta (1970) to the more recent results obtained by quantum mechanical calculations, is presented. The analysis of the already published studies is made pointing out the main factors that must be considered to allow a more reliable understanding of the UV-Vis-NIR spectra of α-Fe2O3. Furthermore, controversies in the calculated results are discussed, analysing the suitability of each of the approaches used. Reasons for differences observed in the experimental data reported in the literature are also discussed.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230040
J. Nascimento, Tiago Alves
EFFECTS OF MULTIPLE STRUCTURES AND TORSIONAL ANHARMONICITY FOR THE HYDROGEN ABSTRACTION REACTIONS OF THE THMETHYL BUTANOATE BY H RADICAL. Thermal rate constants for the hydrogen abstraction reactions of the methyl butanoate (MB) by H radical were estimated by applying the multistructural canonical variational theory with small-curvature tunneling (CVT/SCT). The conformational search was performed at MPWB1K/6-31+G(d,p) level of theory and 68 distinguishable conformers for MB and transition state located. The multistructural and torsional anharmonicity effects were corrected through the rovibrational partition functions calculated with the multistructural method based on a coupled torsional potential, MS-T(C). The MS-CVT/SCT thermal rate constants are shown in good concordance with previous combustion models. After fitting the rate constants in a four-parameters equation, the activation energy showed a temperature dependence. The product branching ratios indicate a preference for (Rα) until 500 K. Above this temperature, the contribution of other reactions becomes relevant, especially for (Rβ).
{"title":"EFEITOS DAS MÚLTIPLAS ESTRUTURAS E DA ANARMONICIDADE TORCIONAL PARA AS REAÇÕES DE ABSTRAÇÃO DE HIDROGÊNIO NO BUTANOATO DE METILA PELO RADICAL H","authors":"J. Nascimento, Tiago Alves","doi":"10.21577/0100-4042.20230040","DOIUrl":"https://doi.org/10.21577/0100-4042.20230040","url":null,"abstract":"EFFECTS OF MULTIPLE STRUCTURES AND TORSIONAL ANHARMONICITY FOR THE HYDROGEN ABSTRACTION REACTIONS OF THE THMETHYL BUTANOATE BY H RADICAL. Thermal rate constants for the hydrogen abstraction reactions of the methyl butanoate (MB) by H radical were estimated by applying the multistructural canonical variational theory with small-curvature tunneling (CVT/SCT). The conformational search was performed at MPWB1K/6-31+G(d,p) level of theory and 68 distinguishable conformers for MB and transition state located. The multistructural and torsional anharmonicity effects were corrected through the rovibrational partition functions calculated with the multistructural method based on a coupled torsional potential, MS-T(C). The MS-CVT/SCT thermal rate constants are shown in good concordance with previous combustion models. After fitting the rate constants in a four-parameters equation, the activation energy showed a temperature dependence. The product branching ratios indicate a preference for (Rα) until 500 K. Above this temperature, the contribution of other reactions becomes relevant, especially for (Rβ).","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230035
Regiane dos Santos, Wellington Pereira De Queirós, F. Damasceno, L. Batista
A COMMENTED TRANSLATION OF ACIDS AND BASES BY GILBERT NEWTON LEWIS. Gilbert Newton Lewis was a distinguished scientist in 20th century History of Chemistry. His work remains relevant for physical chemistry, organic chemistry and coordination chemistry nowadays. Lewis is well known by his propose for chemical bond, based on electron sharing. In 1923 he published two theoretical explanations for acids and bases: the former collaborating with Bronsted and Lowry and the later in his book Valence and the Structure of Atoms and Molecules (1923). In this book, the role of electron pairs in acid base reactions was highlighted decentering explanations from detachment/transfer of hydrogen ion. As a result, more substances could be classified as acids and bases. Also, in the context of organic and coordination chemistry new interpretations for reaction mechanisms showed up. The paper translated here, Acids and Bases (1938), makes a strong empirical description of acids and bases behavior. Lewis designed phenomenological criteria as speed of neutralization reactions, strength of the species acid-base titrations, and its applications as catalysts. In this manuscript, we carried out a commented translation of Lewis Acids and Bases published in 1938, considering it an inspiring source for research and educational applications for Portuguese speaking countries.
{"title":"UMA TRADUÇÃO COMENTADA DO ARTIGO “ÁCIDOS E BASES” DE GILBERT NEWTON LEWIS","authors":"Regiane dos Santos, Wellington Pereira De Queirós, F. Damasceno, L. Batista","doi":"10.21577/0100-4042.20230035","DOIUrl":"https://doi.org/10.21577/0100-4042.20230035","url":null,"abstract":"A COMMENTED TRANSLATION OF ACIDS AND BASES BY GILBERT NEWTON LEWIS. Gilbert Newton Lewis was a distinguished scientist in 20th century History of Chemistry. His work remains relevant for physical chemistry, organic chemistry and coordination chemistry nowadays. Lewis is well known by his propose for chemical bond, based on electron sharing. In 1923 he published two theoretical explanations for acids and bases: the former collaborating with Bronsted and Lowry and the later in his book Valence and the Structure of Atoms and Molecules (1923). In this book, the role of electron pairs in acid base reactions was highlighted decentering explanations from detachment/transfer of hydrogen ion. As a result, more substances could be classified as acids and bases. Also, in the context of organic and coordination chemistry new interpretations for reaction mechanisms showed up. The paper translated here, Acids and Bases (1938), makes a strong empirical description of acids and bases behavior. Lewis designed phenomenological criteria as speed of neutralization reactions, strength of the species acid-base titrations, and its applications as catalysts. In this manuscript, we carried out a commented translation of Lewis Acids and Bases published in 1938, considering it an inspiring source for research and educational applications for Portuguese speaking countries.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-28DOI: 10.21577/0100-4042.20230039
S. Dugheri, G. Cappelli, Niccolò Fanfani, Jacopo Ceccarelli, L. Trevisani, Marco Sarti, Donato Squillaci, Elisabetta Bucaletti, R. Gori, N. Mucci, G. Arcangeli
Solid-phase microextraction (SPME) via on-fiber derivatization with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) and gas chromatographic determination is considered a technique of choice in many analytical fields for formaldehyde (FA) monitoring. Vapor phase adsorption models of experimentally loaded PFBHA on porous divinylbenzene (DVB) SPME were investigated at 60 °C, 35 cm s-1 of air velocity, in a 1-64 min range: with the fiber completely exposed, loaded PFBHA was about 276 µg. Among the models tested, i.e. heat transfer, pseudo-second-order (PSO), Elovich, intra-particle diffusion, extra-particle diffusion and Langmuir, PFBHA adsorption was best fit by the PSO model, showing agreement with experimental data (272 µg). The sampling rate of FA in our conditions, obtained with a permeation tube system, was in agreement with literature (17.4 and 18.3 mL min-1, respectively). Thus, an overall standardization of the sampling phase is presented, leaving the sampling time as the most crucial parameter to be set for future applications.
O-(2,3,4,5,6-五氟苯)-羟胺(PFBHA)纤维衍生固相微萃取(SPME)和气相色谱测定被认为是许多分析领域中甲醛(FA)监测的首选技术。在60°C、35 cm s-1风速、1-64 min的条件下，实验负载的PFBHA在多孔二乙烯基苯(DVB) SPME上的气相吸附模型进行了研究:在纤维完全暴露的情况下，负载的PFBHA约为276µg。在传热模型、伪二阶(PSO)模型、Elovich模型、颗粒内扩散模型、颗粒外扩散模型和Langmuir模型中，PSO模型最适合PFBHA吸附，与实验数据(272µg)吻合。在我们的条件下，通过渗透管系统获得的FA采样率与文献一致(分别为17.4和18.3 mL min-1)。因此，提出了采样阶段的整体标准化，将采样时间作为未来应用中最关键的参数。
{"title":"FORMALDEHYDE ANALYSIS BY SPME ON-FIBER DERIVATIZATION: A STUDY OF THE KINETIC MODELS OF ADSORPTION FOR DIVINYLBENZENE","authors":"S. Dugheri, G. Cappelli, Niccolò Fanfani, Jacopo Ceccarelli, L. Trevisani, Marco Sarti, Donato Squillaci, Elisabetta Bucaletti, R. Gori, N. Mucci, G. Arcangeli","doi":"10.21577/0100-4042.20230039","DOIUrl":"https://doi.org/10.21577/0100-4042.20230039","url":null,"abstract":"Solid-phase microextraction (SPME) via on-fiber derivatization with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) and gas chromatographic determination is considered a technique of choice in many analytical fields for formaldehyde (FA) monitoring. Vapor phase adsorption models of experimentally loaded PFBHA on porous divinylbenzene (DVB) SPME were investigated at 60 °C, 35 cm s-1 of air velocity, in a 1-64 min range: with the fiber completely exposed, loaded PFBHA was about 276 µg. Among the models tested, i.e. heat transfer, pseudo-second-order (PSO), Elovich, intra-particle diffusion, extra-particle diffusion and Langmuir, PFBHA adsorption was best fit by the PSO model, showing agreement with experimental data (272 µg). The sampling rate of FA in our conditions, obtained with a permeation tube system, was in agreement with literature (17.4 and 18.3 mL min-1, respectively). Thus, an overall standardization of the sampling phase is presented, leaving the sampling time as the most crucial parameter to be set for future applications.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-07DOI: 10.21577/0100-4042.20230067
M. Nascimento, N. Menezes, Sabrina T. Martinez, Maria Machado, Gisele da Rocha, Jailson de Andrade
UNCONVENTIONAL POLYAROMATICS COMPOUNDS AND MERCURY IN THE TODOS OS SANTOS BAY, BRAZIL: RECENT ADVANCES AND CONTRIBUTIONS TO BETTER UNDERSTAND OF THEIR ROLE IN THE MARINE ENVIRONMENT. Baía de Todos os Santos (BTS) is the second-largest Brazilian bay; it was the first oil producing region in Brazil, with three large industrial parks in its north-northeast portion. In addition, the BTS has two large ports and a population of around 3 million inhabitants distributed among 14 cities. In the present study, recent studies on contamination by polycyclic aromatic compounds (PACs) and Hg in sediments, water, and biota from the BTS region are presented and critically discussed. Among the PACs, studies evaluating the presence of polycyclic aromatic hydrocarbons (PAHs) and their nitrated (nitro-PAHs), oxygenated derivatives (oxy-PAHs), and those containing atoms of S as a heteroatom (PASHs) are considered, as well as the element Hg distributed in seawater, sediments, and biota. Regarding biomonitoring organisms, recent results on polychaetes, ascidians, and corals are presented. Trends for future studies are presented at the end of the text.
巴西todos OS santos湾的非常规多芳烃化合物和汞:最近的进展和对更好地了解其在海洋环境中的作用的贡献。Baía de Todos os Santos (BTS)是巴西第二大海湾;它是巴西第一个产油区，东北偏北地区有三个大型工业园区。此外，防弹少年团还拥有两个大型港口和分布在14个城市的300多万人口。在本研究中，多环芳香族化合物(PACs)和汞污染的最新研究，从BTS地区的沉积物，水和生物群提出并批判性地讨论。在pac中，考虑了多环芳烃(PAHs)及其硝化(硝基-PAHs)、氧合衍生物(氧基-PAHs)和含S原子的杂原子(PASHs)的存在，以及分布在海水、沉积物和生物群中的汞元素的研究。在生物监测方面，介绍了最近对多毛类、海鞘类和珊瑚的监测结果。未来研究的趋势在文末提出。
{"title":"ESTUDO DE COMPOSTOS POLIAROMÁTICOS NÃO CONVENCIONAIS E MERCÚRIO NA BAÍA DE TODOS OS SANTOS, BRASIL: AVANÇOS RECENTES E CONTRIBUIÇÃO PARA MELHOR COMPREENSÃO DO AMBIENTE MARINHO","authors":"M. Nascimento, N. Menezes, Sabrina T. Martinez, Maria Machado, Gisele da Rocha, Jailson de Andrade","doi":"10.21577/0100-4042.20230067","DOIUrl":"https://doi.org/10.21577/0100-4042.20230067","url":null,"abstract":"UNCONVENTIONAL POLYAROMATICS COMPOUNDS AND MERCURY IN THE TODOS OS SANTOS BAY, BRAZIL: RECENT ADVANCES AND CONTRIBUTIONS TO BETTER UNDERSTAND OF THEIR ROLE IN THE MARINE ENVIRONMENT. Baía de Todos os Santos (BTS) is the second-largest Brazilian bay; it was the first oil producing region in Brazil, with three large industrial parks in its north-northeast portion. In addition, the BTS has two large ports and a population of around 3 million inhabitants distributed among 14 cities. In the present study, recent studies on contamination by polycyclic aromatic compounds (PACs) and Hg in sediments, water, and biota from the BTS region are presented and critically discussed. Among the PACs, studies evaluating the presence of polycyclic aromatic hydrocarbons (PAHs) and their nitrated (nitro-PAHs), oxygenated derivatives (oxy-PAHs), and those containing atoms of S as a heteroatom (PASHs) are considered, as well as the element Hg distributed in seawater, sediments, and biota. Regarding biomonitoring organisms, recent results on polychaetes, ascidians, and corals are presented. Trends for future studies are presented at the end of the text.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68272711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-07DOI: 10.21577/0100-4042.20230031
T. D. de Oliveira, A. Scofield, Luana Silva, A. Lopes, A. Wagener
The present work aimed at evaluating indicators of hydrocarbon sources to sediments from the Solimões River region, in the central Amazon. The 16PAH, the alkylated homologs and molecular markers were investigated. The entire series of alkylated PAH were present and, in some cases, with a distribution observed when oil residues dominate. Nevertheless, hopanes characterizing immature environments undergoing diagenetic transformation were identified in samples from the Solimões River and in surface as well as in core sediment samples from Preto Lake, in the Coari-Manaus stretch. Investigation suggests early diagenesis of the organic matter confirmed by identifying biogenic markers produced during organic matter transformation. Some of these markers derive from incomplete combustion of biomass and are contained in particulate matter formed during forest burning. In the sediments of an industrial area near the city of Manaus, the entire series of mature hopanes was present indicating anthropogenic source of hydrocarbons. The results so far obtained point out the complexity of PAH source appraisal.
{"title":"INVESTIGATION ON THE NATURE AND PROVENANCE OF PAH FOUND IN SEDIMENTS OF THE SOLIMÕES RIVER AND SOME ASSOCIATED LAKES","authors":"T. D. de Oliveira, A. Scofield, Luana Silva, A. Lopes, A. Wagener","doi":"10.21577/0100-4042.20230031","DOIUrl":"https://doi.org/10.21577/0100-4042.20230031","url":null,"abstract":"The present work aimed at evaluating indicators of hydrocarbon sources to sediments from the Solimões River region, in the central Amazon. The 16PAH, the alkylated homologs and molecular markers were investigated. The entire series of alkylated PAH were present and, in some cases, with a distribution observed when oil residues dominate. Nevertheless, hopanes characterizing immature environments undergoing diagenetic transformation were identified in samples from the Solimões River and in surface as well as in core sediment samples from Preto Lake, in the Coari-Manaus stretch. Investigation suggests early diagenesis of the organic matter confirmed by identifying biogenic markers produced during organic matter transformation. Some of these markers derive from incomplete combustion of biomass and are contained in particulate matter formed during forest burning. In the sediments of an industrial area near the city of Manaus, the entire series of mature hopanes was present indicating anthropogenic source of hydrocarbons. The results so far obtained point out the complexity of PAH source appraisal.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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