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1.
J Chromatogr A ; 1645: 462130, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-33848663

RESUMO

Inspired by the outstanding functions of 3-aminopropyltriethoxysilane (APTES), which can be used for functionalization of both covalent organic frameworks (COFs) and substrate surfaces, herein, a proof-of-concept demonstration was carried out by one-step synthesis and immobilization of COF-1 in capillary. COF-1 was grown on the inner wall of capillary using APTES, which played a triple role of catalyst, stabilizer, and connecting arm during the process. The immobilization of COF-1 on silicon surface was confirmed by scanning electron microscopy. Moreover, COF-1 modified capillary (COF-1@capillary) column exhibited excellent performance in the electrochromatographic separation of amino acids. High resolution and separation efficiency (225,378 plates/m for 4-methylbiphenyl) were successfully achieved. Separation of methylbenzene, styrene, ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, 4-methylbiphenyl, naphthalene, and 4-vinylbipheny in the electro-driven mode confirmed the successful growth of COF-1 on the inner wall of capillary. The developed facile method for the immobilization of COF-1 may pave the way for further application prospects of boron-based COFs.


Assuntos
Eletrocromatografia Capilar/métodos , Estruturas Metalorgânicas/química , Derivados de Benzeno/análise , Derivados de Benzeno/química , Derivados de Benzeno/isolamento & purificação , Boro/química , Propilaminas/química , Silanos/química
2.
Artigo em Inglês | MEDLINE | ID: mdl-33671888

RESUMO

Tens of millions of individuals go to gasoline stations on a daily basis in the United States. One of the constituents of gasoline is benzene, a Group 1 carcinogen that has been strongly linked to both occupational and non-occupational leukemias. While benzene content in gasoline is federally regulated, there is approximately a thirty-year data gap in United States research on benzene exposures from pumping gasoline. Using a novel self-sampling protocol with whole air canisters, we conducted a gasoline pumping exposure assessment for benzene, toluene, ethylbenzene, and xylene (BTEX) on Baltimore, MD consumers. Geometric mean exposures (geometric standard deviations) were 3.2 (2.7) ppb,9.5 (3.5) ppb, 2.0 (2.8) ppb, and 7.3 (3.0) ppb, respectively, on 32 samples. Using the benzene exposures, we conducted consumer and occupational probabilistic risk assessments and contextualized the risk with ambient benzene exposure risk. We found that the consumer scenarios did not approach the 1:1,000,000 excess risk management threshold and that the occupational scenario did not exceed the 1:10,000 excess risk management threshold. Further, in all Monte Carlo trials, the ambient risk from benzene exposure exceeded that of pumping risk for consumers, but that in approximately 30% of occupational trials, the pumping risk exceeded the ambient risk.


Assuntos
Neoplasias , Exposição Ocupacional , Baltimore , Benzeno/análise , Benzeno/toxicidade , Derivados de Benzeno/análise , Derivados de Benzeno/toxicidade , Gasolina/análise , Humanos , Exposição Ocupacional/análise , Tolueno/análise , Tolueno/toxicidade , Estados Unidos , Xilenos/análise
3.
Environ Monit Assess ; 193(2): 94, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33507416

RESUMO

Nowadays, workers in petrochemical industry might be exposed to organic volatile compounds, including benzene, toluene, ethylbenzene, and xylene (BTEX). The aim of this study was to investigate the concentration of BTEX contaminations and the biological index in employees of petrochemical sites in the west of Iran. The study was conducted as a cross-sectional study on 30 stations and 60 inhalation and biological samples collected in winter and summer. The NIOSH 2549 and 1501 methods were used for sampling and analyzing the inhaled samples. Gas chromatography-mass spectrometry (GC-MS) equipped with flame ionization detector and high-performance liquid chromatography (HPLC) was used to measure the volatile contaminations. The results showed that the mean concentrations of benzene, toluene, and xylene were significantly different in summer and winter. Significant and strong correlations were observed between the concentrations of benzene, toluene, and xylene and the biological values (r > 0.7). Moreover, the concentration of benzene (ß = 0.836), toluene (ß = 0.718), and xylene (ß = 0.786) predicted the changes in their biological values. Given the hazardous concentrations of benzene and toluene in industrial plants and the correlation of the concentration levels and biological values, management and control strategies should be implemented to eliminate and reduce the pollutants and the effects.


Assuntos
Compostos Orgânicos Voláteis , Xilenos , Benzeno/análise , Derivados de Benzeno/análise , Estudos Transversais , Monitoramento Ambiental , Humanos , Irã (Geográfico) , Tolueno/análise , Xilenos/análise
4.
Food Chem ; 338: 127988, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950866

RESUMO

The potential for tristyrylphenol ethoxylates (TSPEOs) residues to contaminate crops or be released into the environment is of increasing concern, as they are toxic to living organisms. This study determined the dissipation of TSPEO homologues in cucumber under field conditions. TSPEOn (n = 6-29) dissipated more rapidly in cucumber than in soil samples, with half-lives of 1.80-4.30 d and 3.73-6.52 d, respectively. Short-chain TSPEOn (n = 6-11) persisted for longer than other oligomers in soil. Concentrations of the final residues (∑TSPEOs) in cucumber and soil were 24.3-1349 µg/kg and 47.3-1337 µg/kg, respectively. TSP15EO or TSP16EO was the dominant oligomer, with concentrations of 2.30-150 µg/kg. The risk assessment showed that the acute and chronic dietary exposure risks of ∑TSPEOs in cucumber were 0.03-0.57% and 0.05-0.39%, respectively, suggesting little or no health risk to Chinese consumers.


Assuntos
Derivados de Benzeno/análise , Derivados de Benzeno/química , Cucumis sativus/química , Dieta , Solo/química , Estirenos/análise , Estirenos/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/química , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/química
5.
Ecotoxicol Environ Saf ; 203: 111026, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888594

RESUMO

The detection of phenolic compounds, i.e. resorcinol (RC) catechol (CC) and hydroquinone (HQ) are important due to their extremely hazardous impact and poor environmental degradation. In this work, a novel and sensitive composite of electrochemically reduced graphene oxide-poly(Procion Red MX-5B)/gold nanoparticles modified glassy carbon electrode (GCE/ERGO-poly(PR)/AuNPs) was assembled for voltammetric detection of benzenediol isomers (RC, CC, and HQ). The nanocomposite displayed high peak currents towards the oxidation of RC, HQ, and CC compared to non-modified GCE. The peak-to-peak separations were 0.44 and 0.10 V for RC-CC and CC-HQ, respectively. The limit of detections were 53, 53, and 79 nM for HQ, CC, and RC with sensitivities of 4.61, 4.38, and 0.56 µA/µM (S/N = 3), respectively. The nanocomposite displayed adequate reproducibility, besides good stability and acceptable recoveries for wastewater and cosmetic samples analyses.


Assuntos
Compostos Azo/química , Derivados de Benzeno/análise , Técnicas Eletroquímicas/métodos , Ouro/química , Grafite/química , Nanocompostos/química , Poluentes Químicos da Água/análise , Cosméticos/química , Eletrodos , Nanopartículas Metálicas/química , Oxirredução , Reprodutibilidade dos Testes , Águas Residuárias/química
6.
Ecotoxicol Environ Saf ; 203: 111027, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888595

RESUMO

The available evidence on the indoor air quality of operating rooms (ORs) in the Low- and Middle-income Countries (LMICs) is very scarce. Moreover, there is no study on the comparing the concentration of indoor air pollutants in different ORs. Therefore, this study aimed to measure and compare the benzene, toluene, ethylbenzene and xylene (BTEX) concentrations in the air of different ORs in hospitals of Sabzevar, Iran. Moreover, carcinogenic and non-carcinogenic risk of exposure to these pollutants were assessed using Monte Carlo simulations technique. This cross-sectional study was based on volatile organic compounds (VOCs) passive sampling of eight ORs including General surgery, Curettage, Eye surgery, Neurosurgery, Orthopedic, Laparoscopic, Cesarean and Ear, nose, throat (ENT) in two monthly campaigns from November 2019 to February 2020. One-way ANOVA and Post-hoc analyses were used to compare the concentration of BTEX compounds in different ORs. The overall mean (standard deviation (SD)) of benzene, toluene, ethylbenzene, xylene and total BTEX concentrations were 10.0 (1.8), 7.2 (1.9), 1.8 (0.6), 0.4 (0.2) and 19.4 (4.1) µg/m3. The Curettage OR had the highest (12.93 µg/m3) and ENT OR had the lowest (7.42 µg/m3) benzene concentrations. The highest concentrations of toluene, ethylbenzene and total BTEX were observed in General surgery OR. The cancer risks of exposure to benzene in all ORs were higher than the acceptable range recommended by Unite State Environmental Protection Agency (USEPA, 1 × 106). However, the hazard quotient (HQ) values for all ORs were at safe level (HQ < 1). Overall, our study suggested that the concentrations of BTEX compounds were significantly difference in different ORs and benzene had a carcinogenic risk for personnel and surgical staff in different ORs.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Salas Cirúrgicas/normas , Fumaça/análise , Compostos Orgânicos Voláteis/análise , Benzeno/análise , Derivados de Benzeno/análise , Carcinógenos/análise , Estudos Transversais , Monitoramento Ambiental/métodos , Humanos , Irã (Geográfico) , Tolueno/análise , Xilenos/análise
7.
Environ Pollut ; 267: 115464, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32866878

RESUMO

Benzene, toluene, ethylbenzene, and xylene isomers (BTEX) are known to affect environmental air and health quality. In this study, the levels of BTEX compounds were determined in indoor air environments during the winter generated by several different heaters: diesel pot-bellied heater with chimney (DH); electric heater (EH); unfluted gas heater (GH); kerosene heater (KH); and wood pot-bellied heater with chimney (WH). The samples were collected using a diffusion passive adsorbent (activated charcoal) and then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the heaters differ in the quantity of BTEX released during operation. The KH was the most polluted heater based on BTEX measurement, followed by DH. The ∑BTEX for heaters were observed as follows: KH (290 µg m-3); DH (120 µg m-3); GH (84 µg m-3); WH (31 µg m-3); EH (16 µg m-3). Toluene was the predominant compound in all air samples. In KH and DH, the toluene to benzene ratios (T/B) were higher than 4 due to fuel evaporation, while GH had a T/B ratio of 3.9, indicating that the combustion of liquefied petroleum gas (LPG) was the main source. Moreover, a risk assessment was performed to evaluate where the cancer risks (CR) for benzene and ethylbenzene exceeded the critical values (10-6). KH was found to be the most harmful heater for residents, followed by DH and GH. For non-carcinogenic compounds, hazard quotients (HQ) were found to be less than one and thus unlikely to cause health problems.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Benzeno/análise , Derivados de Benzeno/análise , Monitoramento Ambiental , Jordânia , Medição de Risco , Estações do Ano , Tolueno/análise , Xilenos/análise
8.
Environ Sci Pollut Res Int ; 27(35): 44519-44527, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32770338

RESUMO

Urinary benzene, toluene, ethylbenzene, and xylenes (BTEX) can be used as a reliable biomarker of exposure to these pollutants. This cross-sectional study aimed to employ biomonitoring to assess BTEX exposure among South Pars Gas Field (SPGF) workers in Assaluyeh, Iran. Forty employees who were working on the site were recruited as the case group. Besides, 31 administrative employees were recruited as the control group. Pre-shift and post-shift spot urine samples were collected from the subjects in the case group, while the subjects in the control group provided mid-morning urine samples. Overall, 111 urine samples, including 80 samples from the case group and 31 samples from the controls, were collected. Gas chromatography-mass spectrometry (GC/MS) was used to determine the urinary levels of BTEX compounds. The median urinary levels of benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene in the post-shift samples of the exposed group were 1.24, 2.28, 0.5, 1.32, and 1.5 µg/l, respectively. Significant differences were observed in urinary BTEX levels among smokers and non-smokers in both studied groups (p < 0.05). Accordingly, the median urinary BTEX concentrations in smokers were 2 to 6.5 times higher than the corresponding values in non-smoker subjects. Smoking status was the only predictor of the urinary BTEX concentration. Our findings revealed that refinery workers are exposed to significant levels of BTEX compounds. Considering the health risks associated with BTEX exposure for refinery workers, implementation of suitable control strategies, such as using appropriate personal protective equipment and improving on-site ventilation systems, are recommended reducing their exposure to BTEX via the inhalation.


Assuntos
Poluentes Atmosféricos , Exposição Ocupacional , Poluentes Atmosféricos/análise , Benzeno/análise , Derivados de Benzeno/análise , Monitoramento Biológico , Estudos Transversais , Monitoramento Ambiental , Humanos , Irã (Geográfico) , Gás Natural , Exposição Ocupacional/análise , Tolueno/análise , Xilenos/análise
9.
J Environ Sci (China) ; 95: 225-239, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653184

RESUMO

Benzene homologues are important chemical precursors to the formation of ground-level ozone and secondary organic aerosol (SOA) in the atmosphere, in addition, some toxic species are harmful to human health. Strict countermeasures have been taken to fight air pollution since 2013, and total amount control of volatile organic compounds is being promoted in China at present. Therefore, it is important to understand the pollution situation and the control status of ambient benzene homologues in China. This paper reviews research progress from published papers on pollution characteristics, atmospheric photochemical reactivity, health risk assessment and source identification of ambient benzene homologues in recent years in China, and also summarizes policies and countermeasures for the control of ambient benzene homologues and the relevant achievements. The total ambient levels of benzene, toluene, ethylbenzene and xylenes (BTEX) shows a declining tendency from 2001 to 2016 in China. The mass concentrations of BTEX are generally higher in southern regions than in northern regions, and they present vertical decreasing variation characteristics with increasing altitude within the height range of about 5500 m. Toluene has the highest ozone formation potential and SOA formation potential both in urban areas and background areas, while benzene poses an obvious carcinogenic risk to the exposed adult populations in urban areas. Source identification of ambient benzene homologues suggested that local governments should adopt differentiated control strategies for ambient benzene homologues. Several recommendations are put forward for future research and policy-making on the control of ambient benzene homologues in China.


Assuntos
Poluentes Atmosféricos/análise , Benzeno , Adulto , Derivados de Benzeno/análise , China , Monitoramento Ambiental , Humanos , Medição de Risco , Tolueno/análise , Xilenos
10.
Sud Med Ekspert ; 63(4): 39-45, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32686390

RESUMO

The aim of the study was to develop a method for the determination of 2-methoxyhydroxybenzene in biological material. TLC, UV spectrophotometry, HPLC and GC-MS were used in the experiments. The use of a mixture of ethyl acetate-acetone (7:3 by volume) for the isolation of 2-methoxyhydroxybenzene from biological material is justified. Optimal isolation conditions are established. Purification of the substance was carried out by extraction and chromatography in sorbent column (KCC-3) 80/120 µm. For preliminary identification, TLC was used on Sorbfil PTSX-AF-A-UV plates. Confirmation of identification was carried out by the UV spectrum in ethanol by HPLC with the retention time in a 250×4.6 mm column «SunFire C18¼ (mobile phase acetonitrile-0.025 M potassium dihydrogen phosphate solution 6: 4). Confirmation identification and quantification was performed by GC-MS using a fixed phase capillary column of 5% phenyl-95% methyl polysiloxane after derivatization of the analyte with N-trimethylsilyl-N-methyl trifluoroacetamide (heating for 30 min at a temperature of 60 °C). Ions 45, 58, 73, 91, 107, 136, 151, 166, 181, 196 m/z are present in the mass spectrum of the derivative. The validation of the methodology for the determination of 2-methoxyhydroxybenzene in biomaterial based on the application of the GC-MS method was carried out. The compliance of the methodology with the criteria of linearity, selectivity, correctness, precision and stability is established. The detection limit and the limit of quantification are 8 and 15 µg per 100 g of biomaterial, respectively.


Assuntos
Acetona , Derivados de Benzeno , Derivados de Benzeno/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas
11.
J Oleo Sci ; 69(7): 767-770, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32522942

RESUMO

The volatile components produced by Leptolejeunea elliptica (Lejeuneaceae), which is a liverwort grown on the leaves of tea (Camellia sinensis), were collected and analyzed using headspace solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS). 1-Ethyl-4-methoxybenzene (1), 1-ethyl-4-hydroxybenzene (2), and 1-acetoxy-4-ethylbenzene (3) were identified as the major components together with several other phenolic compounds, including 1,2-dimethoxy-4-ethylbenzene, and 4-ethylguaiacol in addition to sesquiterpene hydrocarbons, such as α-selinene, ß-selinene, ß-elemene, and ß-caryophyllene. GC/Olfactometry showed the presence of linalool, acetic acid, isovaleric acid, trans-methyl cinnamate, and trans-4,5-epoxy-(2E)-decenal, as the volatile components produced by L. elliptica.


Assuntos
Hepatófitas/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação , Ácido Acético/análise , Ácido Acético/isolamento & purificação , Anisóis/análise , Anisóis/isolamento & purificação , Derivados de Benzeno/análise , Derivados de Benzeno/isolamento & purificação , Camellia sinensis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Japão , Olfatometria , Fenol/análise , Fenol/isolamento & purificação , Fenóis/análise , Fenóis/isolamento & purificação , Sesquiterpenos Policíclicos/análise , Sesquiterpenos Policíclicos/isolamento & purificação , Sesquiterpenos/análise , Sesquiterpenos/isolamento & purificação , Microextração em Fase Sólida/métodos
12.
Environ Sci Pollut Res Int ; 27(29): 36306-36315, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32556985

RESUMO

Release of analytes from their native matrix and diffusion into the gas phase is the rate-limiting step for the sampling of volatiles in complex solid samples. This limitation is more serious in the solvent-less and solvent-free microextraction sampling strategies. In this research, a three-stage reinforced sampling strategy including high-pressure/sonication/low-pressure was introduced for fast and efficient release of analytes in soil samples. For this purpose, a novel ultrasound-assisted pressure-regulated solid-phase microextraction (UA-PR-SPME) device was developed. It was coupled with gas chromatography-flame ionization detection (GC-FID) and carried out for the determination of benzene, toluene, ethylbenzene, and xylenes (BTEX, as the model analytes) in complex solid samples. Graphene oxide/3-aminopropyltriethoxysilane (GO-APTES) nanocomposite was synthesized and used as the SPME fiber coating. Under optimal conditions, the limits of detection (LODs) were obtained 0.1-0.4 ng/g. The calibration curves were linear over the range of 2.4-5000 ng/g. Relative standard deviations (RSDs%) were calculated 5.1-7.0% (n = 6). The developed technique was employed for the analysis of BTEX in contaminated soil samples.


Assuntos
Poluentes Ambientais , Benzeno/análise , Derivados de Benzeno/análise , Solo , Microextração em Fase Sólida , Tolueno/análise , Xilenos/análise
13.
Environ Monit Assess ; 192(5): 321, 2020 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-32358693

RESUMO

Environmental friendly building materials (BMs) get more attention due to their potential to reduce carbon and air pollutant emissions. However, recycled building materials (RBMs) have no required standard of volatile organic compounds (VOCs) emissions. This study was mainly about the assessment of benzene, toluene, ethylbenzene, and xylene (BTEX), as well as carbonyls emissions from recycled building materials, including gypsum board (GB), calcium silicate board (CSB), fiber cement board (FCB), class I built wall tile (WT), and waterproof gypsum board (WGB). The highest initial and final levels of BTEX were observed on CSB, followed by GB and FCB, and no detectable BTEX were observed on WT and WGB. Benzene was with the highest level among all identified BTEX. Emissions of carbonyls were observed on all materials. The highest initial and final levels of carbonyls were observed on GB, followed by FCB and CSB, while the lowest ones were detected on WT and WGB. The final (96-h) steady-state emissions of BTEX from GB and CSB were 9 and 37 times those from conventional pairs and 27 and 41 times those from low-VOC pairs. Similarly, the final steady-state emissions of carbonyls from GB and CSB were 4.8 and 1.3 times those from conventional pairs and 16 and 2.5 times those from low-VOC pairs. The requirement of evaluation standard for VOC emissions from RBMs is highly recommended to protect consumers. Graphical abstract.


Assuntos
Poluentes Atmosféricos , Materiais de Construção , Monitoramento Ambiental , Poluentes Atmosféricos/análise , Benzeno/análise , Derivados de Benzeno/análise , Materiais de Construção/análise , Reciclagem , Tolueno/análise , Xilenos/análise
14.
Bull Environ Contam Toxicol ; 104(6): 786-791, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32333044

RESUMO

This study aims to determine BTEX concentrations in the Metropolitan Region of Rio de Janeiro (MRRJ, Brazil) and evaluate potential health risks of benzene and ethylbenzene exposure based on the collected data, in 2015, the year before the Rio 2016 Olympic Games. Samples were collected and analyzed following method TO-15 (U.S.EPA). Toluene was the most abundant compound in all samples (mean concentration 16.72 ± 15.70 µg m-3). The average benzene concentration in ambient air (3.44 ± 3.14 µg m-3) was slightly lower than the yearly average "upper assessment threshold", 3.5 µg m-3, established by EU Directive 2008/50/EC. The calculated cancer risk values were > 1 × 10-6 for all samples, clearly indicating a potential cancer risk and the importance of fixed measurements by the monitoring stations to assess ambient air quality in the urban areas of the MRRJ. Calculated ratios for the BTEX species indicate that these compounds are predominantly emitted from vehicular sources with a contribution from industrial sources.


Assuntos
Poluentes Atmosféricos/análise , Derivados de Benzeno/análise , Benzeno/análise , Monitoramento Ambiental/métodos , Exposição por Inalação/análise , Tolueno/análise , Xilenos/análise , Brasil , Cidades , Humanos , Medição de Risco
15.
Food Chem ; 321: 126727, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32283503

RESUMO

Alkenylbenzenes are natural toxins with genotoxic and carcinogenic effects in rodents, which are highly present in condiments frequently consumed. The aim of this study was the development of the first multi-analyte method for the determination of eight alkenylbenzenes (eugenol, methyl eugenol, acetyl eugenol, trans-isoeugenol, safrole, estragole, myristicin and trans-anethole) in different pepper varieties by gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS-Q-Orbitrap) in combination with a simple ultrasound-assisted extraction method (UAE). The method was successfully validated, and it was applied for studying the presence of these analytes in peppers as well as to elucidate the effects of the berries' maturity and the geographical origin on alkenylbenzene contents. The analysis of the pepper samples showed that eugenol (10.5-120 mg/kg), trans-anethole (10.7-42.7 mg/kg) and estragole (2.2-45.7 mg/kg) tended to be the most detected alkenylbenzenes at high levels, whereas trans-isoeugenol (0.69-3.6 mg/kg) and safrole (0.20-3.0 mg/kg) were minor components. Estragole (PubChem CID: 8815); trans-anethole (PubChem CID: 637563); Myristicin (PubChem CID: 4276); Safrole (PubChem CID: 5144); Eugenol (PubChem CID: 3314); Methyl eugenol (PubChem CID: 7127); Acetyl eugenol (PubChem CID: 7136); trans-Isoeugenol (PubChem CID: 853433); Caffeine (PubChem CID: 2519); Dicyclohexylmethanol (PubChem CID: 78197).


Assuntos
Derivados de Benzeno/análise , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Piper nigrum/química , Anisóis/análise , Compostos de Benzil/análise , Fracionamento Químico/métodos , Dioxolanos/análise , Eugenol/análogos & derivados , Eugenol/análise , Piper nigrum/fisiologia , Pirogalol/análogos & derivados , Pirogalol/análise , Safrol/análise , Ultrassom
16.
J Chromatogr A ; 1621: 461035, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32188564

RESUMO

The present work described two triacontyl-bonded silica adsorbents containing different polar embedded groups (i.e. amide- and carbamate-type) for high performance liquid chromatography, which were prepared by covalent surface modification of silica gel with respective pre-synthesized polar-embedded triacontyl (C30) silane. The acylimidazole-mediated method was used for the first time for the synthesis of amide-type alkyl silane, while the carbamate-type silane was obtained via an improved solvent-free procedure. A conventional C30 stationary phase was also developed on the same silica substrate in the similar manner, which was used as a reference column for comparison of the unique mechanisms facilitated and/or furnished by the polar groups. The successful immobilization of the designed C30 species was confirmed by infrared spectroscopy and elemental analysis. In further comparison with an amide-embedded octadecyl (C18) two other conventional C18 stationary phases of different surface chemistry, detailed chromatographic characterization of the C30 series stationary phases was performed in terms of surface density, hydrophobicity, aromatic selectivity, shape selectivity and water tolerance using a diversified range of analytes, including homologous alkylbenzenes, isomeric polycyclic aromatic hydrocarbons, carotenes, congeners of polychlorobiphenyls, aromatic amines, phenolic compounds, estrogens and nucleosides. A high resemblance between the chromatographic behaviors of the two polar-modified C30 stationary phases was observed, meanwhile they demonstrated noticeable differences from non-polar C30 stationary phase. The polar-embedded C30 phases showed satisfactory performance towards the solutes of interest in the studied conditions. The beneficial synergy of the polar groups and the triacontyl chains enabled these polar-enhanced C30 stationary phases to address challenging separation tasks with high selectivity.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Dióxido de Silício/química , Amidas/química , Aminas/análise , Derivados de Benzeno/análise , Carbamatos/química , Carotenoides/análise , Estrogênios/análise , Interações Hidrofóbicas e Hidrofílicas , Nucleosídeos/análise , Fenóis/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Silanos/química , Sílica Gel/química
17.
Mil Med ; 185(Suppl 1): 390-395, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-32074307

RESUMO

BACKGROUND: Military aircrews' health status is critical to their mission readiness, as they perform physically and cognitively demanding tasks in nontraditional work environments. Research Objectives: Our objective is to develop a broad operational risk assessment framework and demonstrate its applicability to health risks to aircrews because of airborne chemical exposure, considering stressors such as heat and exertion. METHODS: Extrapolation of generic exposure standards to military aviation-specific conditions can include computation of risk-relevant internal dosimetry estimates by incorporating changes in breathing patterns and blood flow distribution because of aspects of the in-flight environment. We provide an example of the effects of exertion on peak blood concentrations of 1,2,4-trimethylbenzene computed using a physiologically based pharmacokinetic model. RESULTS: Existing published collections on the effects of flight-related stressors on breathing patterns and blood flow address only a limited number of stressors. Although data exist that can be used to develop operational exposure limits specific to military aircrew activities, efforts to integrate this information in specific chemical assessments have been limited. CONCLUSIONS: Efforts to develop operational exposure limits would benefit from guidance on how to make use of existing assessments and expanded databases of the impact of environmental stressors on adult human physiology.


Assuntos
Aeronaves/instrumentação , Substâncias Perigosas/análise , Exposição Ocupacional/análise , Medicina Aeroespacial/métodos , Medicina Aeroespacial/estatística & dados numéricos , Aeronaves/estatística & dados numéricos , Derivados de Benzeno/análise , Derivados de Benzeno/sangue , Substâncias Perigosas/sangue , Humanos , Exposição Ocupacional/estatística & dados numéricos , Medição de Risco/métodos , Estados Unidos , United States Environmental Protection Agency/organização & administração , United States Environmental Protection Agency/estatística & dados numéricos
18.
Anal Bioanal Chem ; 412(8): 1769-1784, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32043201

RESUMO

Simultaneous speciation of benzenediol isomers (BDIs), 1,2-benzenediol (catechol, CC), 1,3-benzenediol (resorcinol, RS), and 1,4-benzenediol (hydroquinone, HQ), was investigated by differential pulse voltammetry (DPV) using a graphite paste electrode (GPE) modified with Prussian blue-polyaniline nanocomposite. The modified GPE showed good stability, sensitivity, and selectivity properties for all the three BDIs. Prussian blue-doped nanosized polyaniline (PBNS-PANI) was synthesized first by using mechanochemical reactions between aniline and ferric chloride hexahydrate as the oxidants and then followed by the addition of potassium hexacyanoferrate(II) in a solid-state and template-free technique. The material was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The DPV measurements are performed in phosphate electrolyte solution with pH 4.0 at a potential range of - 0.1 to 1.0 V. The proposed modified electrode displayed a strong, stable, and continuous three well-separated oxidation peaks towards electrooxidation at potentials 0.20, 0.31, and 0.76 V for HQ, CC, and RS, respectively. The calibration curves were linear from 1 to 350.5 µM for both HQ and CC, while for RS, it was from 2 to 350.5 µM. The limit of detection was determined to be 0.18, 0.01, and 0.02 µM for HQ, CC, and RS, respectively. The analytical performance of the PBNS-PANI/GPE has been evaluated for simultaneous determination of HQ, CC, and RS in creek water, commercial hair dye, and skin whitening cream samples with satisfactory recoveries between 90 and 106%. Overall, we demonstrated that the presence of NS-PANI and PB resulted in a large redox-active surface area that enabled a promising analytical platform for simultaneous detection of BDIs. Graphical abstract.


Assuntos
Compostos de Anilina/química , Derivados de Benzeno/análise , Ferrocianetos/química , Nanoestruturas/química , Derivados de Benzeno/química , Calibragem , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Isomerismo , Cinética , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Environ Sci Pollut Res Int ; 27(10): 11093-11104, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31955332

RESUMO

The present study was carried out to observe the variation of volatile organic compounds (VOCs) namely benzene, toluene, ethylbenzene, and xylene isomers (BTEX) at three different sites of Delhi, during 2016-2017. Four hourly sampling was carried out day and night separately. Results showed that BTEX concentration was highest in post-monsoon and lowest in monsoon season. Again, daily variation shows that benzene (47%) and toluene (35%) were more during night than day when it was 44% and 33% respectively. Mean concentration of BTEX was observed in following order: ethylbenzene ~ o-xylene < m,p-xylene < toluene < benzene, while overall seasonal variation was observed as follows: post-monsoon > summer > winter > monsoon. Possible emission sources of BTEX were also established through corresponding ratios of individual compounds. Xylene isomers together accounted highest ozone formation potential. The risk assessments of BTEX were carried out in terms of non-cancer (the hazard quotient, HQ) and cancer (the incremental lifetime cancer risk, ILCR) regarding the inhalation exposure only. It was observed that benzene and xylene isomers possessed higher HQs than ethylbenzene and toluene at all sites throughout the study. Again, benzene was found with higher mean ILCR (3.58 × 10-5) than ethylbenzene (1.47 × 10-5).


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Benzeno/análise , Derivados de Benzeno/análise , Monitoramento Ambiental , Índia , Medição de Risco , Tolueno/análise , Xilenos/análise
20.
Chemosphere ; 246: 125722, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31891849

RESUMO

Modeling approaches have been utilized to simulate ambient pollutant concentrations, but very limited efforts have been made to estimate volatile organic compounds in the atmosphere. For this reason, an hourly grid-scale simulation model was developed to determine ambient air concentrations of benzene, toluene, ethylbenzene, and xylene (BTEX). BTEX data were collected over a one-year time frame from the database of the Taiwan Environmental Protection Administration's photochemical assessment monitoring stations. Multivariate linear regression models were used along with correlation analysis to simulate hourly grid-scale BTEX concentrations, using criteria pollutants and selected meteorological variables as predictors. The simulation model was validated in the southern Taiwan area via a portable micro gas chromatography system (n = 121) with significant correlation (r = 0.566**, ** indicated p < 0.01). Moreover, the grid-scale model was applied to areas covering about 72% of the population in Taiwan. A geographic information system (GIS) was used to visualize the spatial distribution of BTEX concentrations from the modeling results. This new grid-scale modeling strategy, which incorporated the GIS output of the simulated data, provides a useful alternative tool for personal exposure analysis and health risk assessment of ambient air BTEX.


Assuntos
Monitoramento Ambiental/métodos , Modelos Químicos , Poluentes Atmosféricos/análise , Atmosfera/análise , Benzeno/análise , Derivados de Benzeno/análise , Sistemas de Informação Geográfica , Humanos , Modelos Lineares , Taiwan , Tolueno/análise , Compostos Orgânicos Voláteis/análise , Xilenos/análise
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