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1.
Biomed Chromatogr ; 38(3): e5746, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37723598

RESUMO

The general population and workers are exposed to organophosphate insecticides, one of the leading chemical classes of pesticides used in rural and urban areas. This paper aims to conduct an integrative review of the most used analytical methods for identifying and quantifying dialkylphosphate-which are metabolites of organophosphate insecticides-in the urine of exposed workers, discussing their advantages, limitations and applicability. Searches utilized the PubMed, the Scientific Electronic Library Online and the Brazilian Digital Library of Theses and Dissertations databases between 2000 and 2021. Twenty-five studies were selected. The extraction methods most used were liquid-liquid extraction (LLE) (36%) and solid-phase extraction (SPE) (36%), with the SPE being more economical in terms of time and amount of solvents needed, and presenting the best percentage of recovery of analytes, when compared with LLE. Nineteen studies (76%) used the gas chromatography method of separation, and among these, 12 records (63%) indicated mass spectrometry used as a detection technology (analyzer). Studies demonstrate that dialkylphosphates are sensitive and representative exposure biomarkers for environmental and occupational organophosphate exposure.


Assuntos
Inseticidas , Praguicidas , Humanos , Inseticidas/análise , Cromatografia Gasosa-Espectrometria de Massas , Compostos Organofosforados/análise , Organofosfatos/urina
2.
Environ Res ; 216(Pt 1): 114391, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36154861

RESUMO

The Eastern Amazon is rich in bauxite ore. The extraction and processing of bauxite lead to the mobilization of Aluminum (Al) and other metals in environmental. We evaluated the metals (Al, Mn, Ba, and Cr) concentration in tissue, water, and sediment associated with antioxidant and oxidative damage responses in Bryconops caudomaculatus. The samplings were done in two hydrological periods (post-rain and post-dry periods) and at three points, located at two rivers: one in the surroundings of the mining area (P1) and other inside the mining area, upstream (P2), and downstream (P3). Defense antioxidant system biomarkers analyzed were total antioxidant capacity (ACAP) and glutathione-S-transferase (GST) activity. As an oxidative damage biomarker, the lipoperoxidation (LPO) was evaluated. Metals concentrations in the water and sediment were higher in the post-rain period compared to post-dry period. The water samples were acidic, with dissolved Al concentrations above the values established by local legislation at all points. In the gills, the metals accumulation was higher in fish from in the surrounding and upstream sites, and in the liver, was higher in fish from downstream site. Fish from the surrounding had increased antioxidant defenses, with higher ACAP in all tissues and higher GST in the gills. Consequently, they had lower levels of LPO. Fish from the mining area had decreased antioxidant defenses, with lower ACAP in all tissues and lower GST in the gills. Consequently, they had higher levels of LPO, indicating oxidative stress. The fish muscle was not responsive to GST and LPO at all sites. We conclude that the oxidative stress observed in the gills and liver of B. caudomaculatus from the area modified by the mining activity reflected the local anthropogenic impact status.


Assuntos
Caraciformes , Poluentes Químicos da Água , Animais , Caraciformes/metabolismo , Antioxidantes/metabolismo , Peroxidação de Lipídeos , Óxido de Alumínio , Estresse Oxidativo/fisiologia , Brânquias/metabolismo , Metais/toxicidade , Metais/metabolismo , Biomarcadores/metabolismo , Fígado/química , Água , Poluentes Químicos da Água/análise , Glutationa Transferase/metabolismo
3.
Environ Monit Assess ; 196(1): 10, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38049584

RESUMO

The general population and workers are exposed to organophosphate insecticides, one of the leading chemical classes of pesticides used in rural and urban areas, in the control of arboviruses and agriculture. These pesticides cause environmental/occupational exposure and associated risks to human and environmental health. The objective of this study was to carry out an integrative review of epidemiological studies that identified and quantified dialkylphosphate metabolites in the urine of exposed populations, focusing on the vector control workers, discussing the application and the results found. Searches utilized the Pubmed, Scielo, and the Brazilian Digital Library of Theses and Dissertations (BDTD) databases between 2000 and 2021. From the 194 selected studies, 75 (39%) were with children/adolescents, 48 (24%) with rural workers, 36 (19%) with the general population, 27 (14%) with pregnant women, and 9 (4%) with vector control workers. The total dialkylphosphate concentrations found in the occupationally exposed population were higher than in the general population. Studies demonstrate that dialkylphosphates are sensitive and representative exposure biomarkers for environmental and occupational organophosphate exposure. The work revealed a lack of studies with vector control workers and a lack of studies in developing countries.


Assuntos
Inseticidas , Exposição Ocupacional , Praguicidas , Criança , Humanos , Feminino , Gravidez , Adolescente , Monitoramento Ambiental , Compostos Organofosforados , Exposição Ambiental/análise , Organofosfatos
4.
Eur J Nutr ; 61(7): 3357-3366, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35505122

RESUMO

PURPOSE: This study aimed to investigate the effects of AGE on microvascular reactivity, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in older individuals at high risk for cardiovascular disease (CVD). Urinary thiosulfate was also investigated as an indirect marker of endogenous hydrogen sulfide (H2S) synthesis. The study was conducted in a randomized, double-blind, crossover, and placebo-controlled way. METHODS: Twenty-eight participants (14 male), 67 ± 6 years old with CVD risk factors, ingested 2.4 g of AGE or placebo (PLA). Near-infrared spectroscopy evaluated tissue oxygen saturation (StO2) during a vascular occlusion test (30 s baseline, 5 min occlusion, and 2 min reperfusion). The upslope of StO2 signal after cuff release was calculated to measure microvascular reactivity. Urinary thiosulfate levels were measured using a high-performance liquid chromatography system. RESULTS: The upslope of StO2 was significantly faster after AGE (1.01 ± 0.37% s-1) intake compared to PLA (0.83 ± 0.35% s-1; P < 0.001; d = 0.50). Relative changes in Δ% SBP from pre- to post-AGE intake (- 5.17 ± 5.77%) was significantly different compared to Δ% PLA (0.32 ± 5.99%; P = 0.001; d = 0.93). No significant changes in urinary thiosulfate concentrations were observed between interventions. Moreover, no significant gender effect in any parameter assessed was found. CONCLUSION: This study demonstrated that a single dose of AGE improved microvascular reactivity in older adults at risk of CVD despite such an effect was not linked with urinary thiosulfate levels. This trial was registered at clinicaltrials.gov as NCT04008693 (May 19, 2020).


Assuntos
Doenças Cardiovasculares , Alho , Sulfeto de Hidrogênio , Idoso , Doenças Cardiovasculares/prevenção & controle , Humanos , Sulfeto de Hidrogênio/metabolismo , Masculino , Microcirculação/fisiologia , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Consumo de Oxigênio/fisiologia , Extratos Vegetais/metabolismo , Poliésteres/metabolismo , Tiossulfatos/metabolismo
5.
Biomarkers ; 26(6): 539-547, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34082618

RESUMO

BACKGROUND: Oxidative stress may be an important mechanism linking pesticide exposure to several diseases. We evaluated the association between pesticide exposures and oxidative stress biomarkers in Brazilian agricultural workers. METHODS: A cross-sectional study was conducted in healthy agricultural (N = 52) and non-agricultural workers (N = 68) in a rural community in Rio de Janeiro State, Brazil. Regular pesticide use, sociodemographic, and lifestyle information was obtained by questionnaire. Oxidative stress biomarkers (N = 7) were measured in serum and plasma. We calculated percent differences and 95% confidence intervals (CI) in oxidative stress biomarkers for use of pesticides adjusted for sex, age, education, smoking, and alcohol consumption, using multiple linear regression. RESULTS: Living close to or in the fields was associated with glutathione peroxidase activity but not with any other markers. We observed significant positive associations between 8-isoprostane levels and activities of glutathione reductase, glutathione peroxidase, and glutathione-S-transferase with reported use of certain insecticides, fungicides, and herbicides. Our results also indicate a significant and negative association between glutathione-S-transferase activity and insecticide use. CONCLUSIONS: These findings suggest that use of pesticides may be associated with differences in oxidative stress biomarkers.


Assuntos
Fazendeiros , Exposição Ocupacional , Estresse Oxidativo , Praguicidas/toxicidade , Adulto , Biomarcadores/sangue , Brasil , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
6.
Proc Natl Acad Sci U S A ; 115(42): E9765-E9772, 2018 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-30279179

RESUMO

This work investigates whether genetic makeup moderates the effects of education on health. Low statistical power and endogenous measures of environment have been obstacles to the credible estimation of such gene-by-environment interactions. We overcome these obstacles by combining a natural experiment that generated variation in secondary education with polygenic scores for a quarter-million individuals. The additional schooling affected body size, lung function, and blood pressure in middle age. The improvements in body size and lung function were larger for individuals with high genetic predisposition to obesity. As a result, education reduced the gap in unhealthy body size between those in the top and bottom terciles of genetic risk of obesity from 20 to 6 percentage points.


Assuntos
Índice de Massa Corporal , Escolaridade , Herança Multifatorial , Obesidade/prevenção & controle , Adolescente , Tamanho Corporal , Criança , Pré-Escolar , Predisposição Genética para Doença , Humanos , Lactente , Recém-Nascido , Obesidade/epidemiologia , Obesidade/genética , Fatores de Risco , Determinantes Sociais da Saúde
7.
Pestic Biochem Physiol ; 165: 104464, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32359546

RESUMO

The glutathione S-transferases (GSTs) are enzymes involved in several distinct biological processes. In insects, the GSTs, especially delta and epsilon classes, play a key role in the metabolism of xenobiotics used to control insect populations. Here, we investigated its potential role in temephos resistance, examining the GSTE2 gene from susceptible (RecL) and resistant (RecR) strains of the mosquito Aedes aegypti, vector for several pathogenic arboviruses. Total GST enzymatic activity and the GSTE2 gene expression profile were evaluated, with the GSTE2 cDNA and genomic loci sequenced from both strains. Recombinant GSTE2 and mutants were produced in a heterologous expression system and assayed for enzyme kinetic parameters. These proteins also had their 3D structure predicted through molecular modeling. Our results showed that RecR has a profile of total GST enzymatic activity higher than RecL, with the expression of the GSTE2 gene in resistant larvae increasing six folds. Four exclusive RecR mutations were observed (L111S, I150V, E178A and A198E), which were absent in the laboratory susceptible strains. The enzymatic activity of the recombinant GSTE2 showed different kinetic parameters, with the GSTE2 RecR showing an enhanced ability to metabolize its substrate. The I150V mutation was shown to induce significant changes in catalytic parameters and a 3D modeling of GSTE2 mapped two of the RecR changes (L111S and I150V) near the enzyme's catalytic pocket, also implying an impact on its catalytic activity. Our results reinforce a potential role for GSTE2 in the metabolic resistance phenotype while contributing to the understanding of the molecular basis for the resistance mechanism.


Assuntos
Aedes , Inseticidas , Animais , Resistência a Inseticidas , Mosquitos Vetores , Temefós
8.
Biomed Chromatogr ; 33(11): e4669, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31368119

RESUMO

The extent of adulteration of dietary supplements has significantly increased in recent years. This situation worries health authorities and requires auxiliary analytical tools for the investigation of illegal substances purposely added. Ion exchange chromatography with conductivity detection is a consolidated analytical technique for the determination of inorganic compounds in various matrices. This technique has been applied to the pharmaceutical characterization of mainly impurities and degradation products. This work presents a new approach to ion exchange chromatography as a screening method to investigate the presence of amfepramone, femproporex, sibutramine, bisacodyl and amiloride in dietary supplements advertised for weight loss. The method was optimized and validated using a Metrosep C4 100/4.0 cation exchange column. The mobile phase consisted of 1.8 mm HNO3 containing 2% acetonitrile (v/v), with a flow rate of 0.9 ml min-1 , and nonsuppressed conductivity detection was applied. The limits of detection and quantification varied from 1.01 to 3.62 mg L-1 and from 1.48 to 8.72 mg L-1 , respectively. The proposed method was successful applied to 78 solid dietary supplement samples, in two of which adulterations were found. Moreover, ion exchange chromatography with conductivity detection could be easily used for quality control without prior complex sample pre-treatment.


Assuntos
Cromatografia por Troca Iônica/métodos , Suplementos Nutricionais/análise , Contaminação de Medicamentos , Condutividade Elétrica , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
9.
Inflammopharmacology ; 27(2): 323-338, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29327283

RESUMO

Persea americana, popularly known as avocado, has been empirically used as analgesic and anti-inflammatory including in the skin disorder treatment. Species of the genus Persea also show a photoprotective effect against UVB radiation. We investigated the antinociceptive and anti-inflammatory effects from a topical formulation containing the P. americana leaf extract in a UVB irradiation-induced burn model in mice and performed a gel-formulation stability study. The antinociceptive and anti-inflammatory effect was evaluated through mechanical allodynia, paw oedema, and inflammatory cell infiltration. Phenolic compounds were quantified by UHPLC-MS/MS. The gel-formulation stability study was performed analyzing organoleptic characteristics, pH, and viscosity. P. americana (3%) gel was able to prevent the UVB irradiation-induced mechanical allodynia on the 2nd and 3rd day after irradiation with maximum inhibition of 60 ± 12% at 2nd day. Such effect may be attributed, at least in part, due the presence of (+)-catechin (302.2 ± 4.9 µg/g) followed by chlorogenic acid (130 ± 5.1 µg/g) and rutin (102.4 ± 0.9 µg/g) found in the extract. The gel was not able to prevent the inflammatory parameters such as edema and leukocyte infiltration induced by UVB irradiation. No changes important were detected in the stability study, mainly in low temperature. Our results suggest that P. americana gel-formulation, which presented stability, ensuring its quality and the therapeutic effect, could be an interesting strategy for the treatment of the pain associated with sunburn; this effect could be attributed to its biological constituents, especially catechin, chlorogenic acid, and rutin.


Assuntos
Analgésicos/farmacologia , Persea/química , Extratos Vegetais/farmacologia , Dermatopatias/tratamento farmacológico , Raios Ultravioleta/efeitos adversos , Animais , Anti-Inflamatórios/farmacologia , Edema/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Leucócitos/efeitos dos fármacos , Masculino , Camundongos , Fitoterapia/métodos
10.
Anal Biochem ; 545: 98-103, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29305840

RESUMO

An analytical method utilizing liquid chromatography coupled to mass spectrometry with electrospray ionization has been developed for the identification of prostaglandins (PGs) in cerebral tissues. The five compounds identified (thromboxane B2, prostaglandin E2, prostaglandin D2, 6-keto-prostaglandin F1 alpha and prostaglandin F2 alpha) are cellular mediators of inflammation and are involved in a variety of physiological and pathological processes by acting on membrane receptors on the surfaces of target cells. The parameters of the electrospray ionization interface were optimized to obtain the highest possible sensitivity for all compounds studied. The limits of detection ranged from 0.25 to 1.09 µg L-1, and the limits of quantification ranged from 0.83 to 3.64 µg L-1. The method was validated and applied to samples of brain tissue from five mice. The sample concentrations of the four prostaglandins quantified ranged from 375 ȵg L-1for prostaglandin E2 to 6602 µg L-1 for prostaglandin D2. An advantage of this work that should be emphasized is the fast response of the method, which allows to obtaining the lipid profile after a 3 min chromatographic run.


Assuntos
Cérebro/química , Prostaglandinas/análise , Animais , Cromatografia Líquida de Alta Pressão , Camundongos , Estrutura Molecular , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
11.
J Pediatr Gastroenterol Nutr ; 67(5): 671-676, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29985872

RESUMO

BACKGROUND AND OBJECTIVES: Parenteral nutrition (PN) administered to newborns (NB) may be contaminated with polycyclic aromatic hydrocarbons (PAHs) and may therefore increase the contact with these toxicants in very early life stages. The aim of the study is to determine to what extent, if any, commercial products for PN are contaminated with PAHs and to determine whether these contaminants, when present in the bag content, are delivered to NB and whether 1-hydroxypyrene (1-HP), the pyrene metabolite, can be detected in the urine of exposed NB. METHODS: Commercial products and the bags administered to 10 NB during their period in the NICU were analyzed for the 16 priority US Environmental Protection Agency PAHs. Urine samples were collected and analyzed for their 1-HP content. Urine samples of a control group composed of 8 breastfed NB were also analyzed for the determination of 1-HP. RESULTS: From 9 different commercial products used to compound PN bags, 6 were contaminated with PAHs, with total concentrations varying from 0.02 to 10.56 mg/L. In the bags administered to the NB, this sum varied from 0.01 to 6.30 mg/L with a mean of 2.62 mg/L. Therefore, for each 100 mL PN, an average load of 0.26 mg PAHs was observed. The majority of the urine samples taken from NB in the study group (80%) contained 1-HP, but it was not detected in the urine of any baby in the control group. CONCLUSIONS: The contamination of PN with PAHs poses a critical toxicological risk. The elevated contaminant concentrations and the parenteral way of administration make this source of PAHs considerably worse than any other, including maternal exposure to environmental pollution or tobacco.


Assuntos
Exposição Dietética/análise , Contaminação de Alimentos/análise , Nutrição Parenteral/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/análise , Feminino , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Pediátrica , Masculino , Pirenos/urina
12.
Inflammopharmacology ; 26(2): 505-519, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28801728

RESUMO

Gout is a disorder that triggers a severe inflammatory reaction which generates episodes of intense pain and discomfort to the patient. Arctium minus (Hill) Bernh. (Asteraceae) is known as "burdock" and displays anti-inflammatory, antinociceptive, against rheumatic pain and radical-scavenging activities. Species of the genus Arctium have been used in assistant therapy of gout and other inflammatory processes. We investigated the antinociceptive and anti-edematogenic effects of the crude extract of A. minus seeds in an acute gout attack model induced by intra-articular injection of monosodium urate (MSU) crystals in adult male Swiss mice (25-30 g). The crude extract of A. minus (100 mg/kg, p.o.) reduced the mechanical allodynia induced by the injection of MSU (1.25 mg/site, i.a.) from 4 until 8 h after its administration. A. minus seeds crude extract prevented mechanical allodynia at doses of 30 and 100 mg/kg, but not 10 mg/kg. Allopurinol (10 µg/mL) and A. minus crude extract (10-300 µg/mL) inhibited the xanthine oxidase activity in vitro. The A. minus seeds crude extract did not cause adverse effects since did not change the toxicological parameters evaluated. A. minus crude extract can be used as an assistant therapy of gout pain, supporting its traditional use, without causing adverse effects.


Assuntos
Analgésicos/farmacologia , Arctium/química , Gota/tratamento farmacológico , Extratos Vegetais/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Modelos Animais de Doenças , Edema/tratamento farmacológico , Edema/metabolismo , Gota/metabolismo , Hiperalgesia/tratamento farmacológico , Hiperalgesia/metabolismo , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Masculino , Camundongos , Xantina Oxidase/metabolismo
13.
Am Econ Rev ; 106(2): 260-284, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28003681

RESUMO

We study the effect of financial resources on decision-making. Low-income U.S. households are randomly assigned to receive an online survey before or after payday. The survey collects measures of cognitive function and administers risk and intertemporal choice tasks. The study design generates variation in cash, checking and savings balances, and expenditures. Before-payday participants behave as if they are more present-biased when making intertemporal choices about monetary rewards but not when making intertemporal choices about non-monetary real-effort tasks. Nor do we find before-after differences in risk-taking, the quality of decision-making, the performance in cognitive function tasks, or in heuristic judgments.

14.
Int J Food Sci Nutr ; 67(7): 789-96, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27381473

RESUMO

Food and agricultural industries generate substantial quantities of phenolic-rich by-products that could be valuable natural sources of antioxidants. The aim of this study was to identify and quantify the phenolic compounds and radical scavenging activities of two by-products (pomace and lees) from Vitis vinifera L. cv Pinot noir. We found a different distribution of phenolic classes (flavanols, flavonols, phenolic acids and stilbenes) and singular scavenging activity against free radicals (hydroxyl, superoxide and peroxyl radicals). The major class of phenolics in pomace was flavanols and in lees was flavonols, with catechin (117.9 ± 2.5 µg g(-1)) and quercetin (42.4 ± 1.2 µg g(-1)) being the most abundant individual compounds. We also found high potential on scavenging activity against superoxide radicals in pomace (80% of scavenging activity) and radical peroxyl (67% scavenging activity). These results show the possibility of using Pinot noir by-products as promising additives or as a source for the development of new products in different segments of the food and cosmetic industries.


Assuntos
Antioxidantes/análise , Frutas/química , Fenóis/análise , Vitis/química , Catequina/análise , Cromatografia Líquida de Alta Pressão , Flavonoides/análise , Flavonóis/análise , Hidroxibenzoatos/análise , Quercetina/análise , Estilbenos/análise , Espectrometria de Massas em Tandem
15.
Bull Environ Contam Toxicol ; 97(4): 456-62, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27393328

RESUMO

The antimicrobial activity of silver nanoparticles (AgNP) makes them useful in a wide range of products although their environmental impact is still uncertain. The main goal of this study was to evaluate short-term effects induced by AgNP on gills oxidative status and bacterial communities living at the skin mucus of zebrafish. Both the number of bacteria colony forming units and bacteria growth obtained from skin mucus were lower in all concentrations tested (25, 50 and 100 µg nAg/L). Besides, AgNP exposure caused a significant decrease in bacteria growth in zebrafish exposed to 100 µg nAg/L. AgNP accumulated in zebrafish gills at both highest concentrations tested, but this accumulation did not appear to result in oxidative stress. Overall the results indicated toxicological effects of AgNP on bacteria communities living at the zebrafish mucus surface. Although silver accumulation was verified in gills, no evidence of toxicity in terms of oxidative stress was found.


Assuntos
Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bactérias/efeitos dos fármacos , Brânquias/metabolismo , Peixe-Zebra
16.
J Consum Aff ; 50(2): 263-285, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-31802782

RESUMO

We document that immigrants in the United States differ from natives in several aspects relevant for their financial decision making. Based on these differences, we designed novel financial education materials targeted at US immigrants and their children and evaluated their effectiveness using a randomized control trial. To the best of our knowledge, this is the first rigorous evaluation of financial education programs targeted at this population. Compared to a control group, the groups that received the one-time educational intervention were more likely to correctly answer financial knowledge questions immediately after the intervention. The estimated effects of this one-time intervention on knowledge were large, but most of them faded away after six months. Moreover, we find little effect of the treatments on intended financial behavior measures, both immediately and six months later. Our results point to the efficacy of this type of educational material in informing immigrants and their children about important financial information that they are unfamiliar with, including information related to their immigrant status. However, they also suggest that a priority for future research should be to test whether repeated opportunities for learning can increase financial knowledge retention and lead to behavior change.

17.
J Sep Sci ; 38(23): 4055-62, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26446274

RESUMO

Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 µg/L for nitrated and from 0.1 to 6.6 µg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 µg/L for nitrated and 0.3-8.9 µg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected.

18.
J Sep Sci ; 38(13): 2238-44, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25885756

RESUMO

An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 µg/L and the limits of quantification ranged from 1.7 to 1550 µg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene.

19.
Electrophoresis ; 35(21-22): 3212-30, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25070473

RESUMO

This review aims to describe the CE methods utilized for the determination of adulterants in herbal-based formulations marketed for different therapeutic purposes. The CE methods for screening and determination of pharmacologic adulterants are reviewed on the basis of the CE techniques and their detection methods. CZE and MEKC methods coupled to optical (UV), capacitively coupled contactless conductivity, and MS detection modes are discussed and reviewed. Worldwide adulteration cases related to pharmaceutical formulations containing herbs as the main active products are presented covering all the works published in the last four decades.


Assuntos
Contaminação de Medicamentos , Eletroforese Capilar/métodos , Preparações de Plantas , Espectrometria de Massas , Preparações de Plantas/análise , Preparações de Plantas/química , Preparações de Plantas/normas
20.
J Polit Econ Microecon ; 2(1): 43-76, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38646197

RESUMO

Many financial situations present individuals with simple alternatives to solving complex problems. The value of these alternatives depends on whether individuals are sophisticated and know when they are better off opting out of complexity. We tested complexity's effects and evaluated sophistication in a large and diverse sample. We randomly assigned both complexity to portfolio problems and the offer of a simple alternative to portfolio choice. The less-skilled earn lower returns under complexity because they often opt out when the simple alternative is dominated. To interpret the findings, we develop a novel method for estimating the structural parameters of a rational inattention model. The structural estimates are consistent with substantial sophistication. Large fractions of the money that the low-skilled lose by opting out can be justified by their higher costs of attention.

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