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1.
J Chromatogr A ; 1697: 463993, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37084695

RESUMO

Herein, a copper-chromium-layered double hydroxide (Cu/Cr-LDH) was synthesized by the co-precipitation method. The Cu/Cr-LDH was intercalated to the Keggin-type polyoxometalate (H3PW12O40). The modified LDH accommodated in the pores of hollow fiber (HF), to prepare the extracting device for the HF-solid phase microextraction method (HF-SPME). The method was used for the extraction of 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6- trichlorophenol from tap water, river water, and tea sample. The extracted target analytes were quantified via high-performance liquid chromatography-UV detection. The figures of merit of the method such as, linear dynamic ranges (LDRs), limit of detections (LODs) and, limit of quantifications (LOQs), were determined based on the obtained optimum condition. Based on the results, the LDR was between 1 and 500 µg L - 1 and r2 higher than 0.9960. The LODs and LOQs were obtained in the ranges of 0.28-0.36 µg L - 1 and 0.92-1.1 µg L - 1, respectively. The relative standard deviations ((RSDs% for inter-and intra-day) of the method for the extraction of target analytes were calculated in two different concentrations of (2 and 10 µg L - 1) and (5 and 10 µg L - 1) between 3.70% - 5.30% and 3.50% - 5.70%-respectively. The enrichment factors were obtained between 57 and 61. In order to investigate the accuracy of the method, also the relative recovery was obtained, between 93 and 105%. Finally, the proposed method was used for the extraction of the selected analytes in different water and tea samples.


Assuntos
Clorofenóis , Microextração em Fase Líquida , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Sólida/métodos , Ácido Fosfotúngstico/análise , Cobre/análise , Porosidade , Água/química , Clorofenóis/análise , Chá , Microextração em Fase Líquida/métodos
2.
J Chromatogr A ; 1673: 463077, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35508095

RESUMO

In this work, a porous extended network covalent organic framework designated as TP-NDA-COF was synthesized by the reaction of 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (TP) and 1,5-naphthalenediamine (NDA). The structure and morphology of the TP-NDA-COF was characterized by means of Fourier transform infrared spectra (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The TP-NDA-COF was applied as a solid-phase extraction adsorbent for the extraction of some chlorophenols from water and lemon black tea beverage samples prior to high performance liquid chromatography-UV detection. The main experimental parameters that affect the extraction efficiency including the type and volume of eluent, sample solution volume, sample loading rate and sample solution pH were investigated. Under the optimal conditions, the calibration curves were linear in the range of 0.30-60.0 ng mL-1 with the determination coefficients (R2) of 0.9996-0.9998 for water samples and in the range of 0.60-60.0 ng mL-1 with the R2 values from 0.9990 to 0.9996 for beverage samples. At the signal to noise ratio of 3 (S/N = 3), the method LODs for the analytes were 0.10-0.15 ng mL-1 for water samples and 0.20-0.50 ng mL-1 for lemon black tea beverage, respectively. Good repeatability was achieved with the relative standard deviations of less than 7%. The results showed that the SPE-HPLC method can be used for the determination of chlorophenols in environmental water and foodstuffs samples.


Assuntos
Clorofenóis , Estruturas Metalorgânicas , Adsorção , Clorofenóis/análise , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Estruturas Metalorgânicas/química , Extração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Chá/química , Água/química
3.
Food Chem ; 297: 124962, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253288

RESUMO

Ferrocene-based nanoporous organic polymer (Fc-NOP) was used as solid-phase extraction (SPE) adsorbent and showed excellent adsorption capacity for chlorophenols (CPs) compared with commercial C18 and multi-walled carbon nanotubes. Then, a SPE method with Fc-NOP packed cartridge combined with HPLC-UV detection was developed to determine CPs in tap water, black tea drinks and peach juice samples. Under optimal conditions, the detection limits of the method measured at the signal to noise ratio of 3 (S/N = 3) were 0.04-0.06 ng mL-1 for tap water and 0.10-0.20 ng mL-1 for black tea drinks and peach juice samples. Satisfactory method recoveries were achieved in the range of 87.6-119% with relative standard deviations of 3.11-7.83%. Result proved that this method was a sensitive and efficient method for determination of trace CPs in foods. The extraction result for more other compounds confirmed that the developed method had a great application potential for analysis of other trace pollutants in food samples.


Assuntos
Clorofenóis/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Polímeros/química , Extração em Fase Sólida/métodos , Adsorção , Clorofenóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Compostos Ferrosos/química , Análise de Alimentos/instrumentação , Água Doce/análise , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Metalocenos/química , Nanoporos , Nanotubos de Carbono/química , Prunus persica/química , Extração em Fase Sólida/instrumentação , Chá/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
4.
Chemosphere ; 227: 670-680, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31022668

RESUMO

Chlorophenols (CPs), including pentachlorophenol (PCP), are chemicals of concern due to their toxicity and persistence. Here we describe a successful reactor-based remediation of CP-contaminated soil and assess changes in the toxicity patterns and bacterial communities during the remediation. The remediation consisted of separating half of the contaminated soil to be ground (samples M) in order to test whether the grinding expedited the remediation, the other half was left unground (samples P). Both soils were mixed with wastewater treatment sludge to increase their bacterial diversity and facilitate the degradation of CPs, and the resultant mixtures were placed in 2 bioreactors, M and P, operated for 16 months under anaerobic conditions to favor dehalogenation and for an additional 16 months under aerobic conditions to achieve complete mineralization. Samples were taken every 4 months for toxicity and microbial analyses. The results showed a 64% removal of total CPs (ΣCPs) in reactor P after just 18 months of remediation, whereas similar depletion in reactor M occurred after ∼25 months, indicating that the grinding decelerated the remediation. By the end of the experiment, both reactors achieved 93.5-95% removal. The toxicity tests showed a decrease in toxicity as the remediation progressed. The succession of bacterial communities over time was significantly associated with pH, anaerobic/aerobic phase and the concentration of the majority of CP congeners. Our data indicate that the supplementation of contaminated soil with sludge and further incubation in pilot-scale bioreactors under consecutive anaerobic-aerobic conditions proved to be effective at the remediation of CP-contaminated soil.


Assuntos
Reatores Biológicos/microbiologia , Clorofenóis/análise , Microbiologia do Solo , Poluentes do Solo/análise , Solo/química , Aerobiose , Anaerobiose , Biodegradação Ambiental , Pentaclorofenol/análise , Projetos Piloto , Esgotos/microbiologia
5.
Sci Rep ; 8(1): 8186, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29844501

RESUMO

Evidence of bisphenols' obesogenic effects on humans is mixed and inconsistent. We aimed to explore the presence of bisphenol A (BPA), bisphenol F (BPF) and chlorinated BPA (ClBPA), collectively called the bisphenols, in different brain regions and their association with obesity using post-mortem hypothalamic and white matter brain material from twelve pairs of obese (body mass index (BMI) >30 kg/m2) and normal-weight individuals (BMI <25 kg/m2). Mean ratios of hypothalamus:white matter for BPA, BPF and ClBPA were 1.5, 0.92, 0.95, respectively, suggesting no preferential accumulation of the bisphenols in the grey matter (hypothalamic) or white matter-enriched brain areas. We observed differences in hypothalamic concentrations among the bisphenols, with highest median level detected for ClBPA (median: 2.4 ng/g), followed by BPF (2.2 ng/g) and BPA (1.2 ng/g); similar ranking was observed for the white matter samples (median for: ClBPA-2.5 ng/g, BPF-2.3 ng/g, and BPA-1.0 ng/g). Furthermore, all bisphenol concentrations, except for white-matter BPF were associated with obesity (p < 0.05). This is the first study reporting the presence of bisphenols in two distinct regions of the human brain. Bisphenols accumulation in the white matter-enriched brain tissue could signify that they are able to cross the blood-brain barrier.


Assuntos
Compostos Benzidrílicos/metabolismo , Encéfalo/metabolismo , Clorofenóis/metabolismo , Disruptores Endócrinos/metabolismo , Poluentes Ambientais/metabolismo , Obesidade/metabolismo , Fenóis/metabolismo , Tecido Adiposo/metabolismo , Compostos Benzidrílicos/efeitos adversos , Compostos Benzidrílicos/análise , Índice de Massa Corporal , Clorofenóis/efeitos adversos , Clorofenóis/análise , Disruptores Endócrinos/efeitos adversos , Disruptores Endócrinos/análise , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Poluentes Ambientais/efeitos adversos , Poluentes Ambientais/análise , Halogenação , Humanos , Hipotálamo/metabolismo , Obesidade/induzido quimicamente , Fenóis/efeitos adversos , Fenóis/análise , Substância Branca/metabolismo
6.
Molecules ; 22(10)2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-29053615

RESUMO

The residue dynamics and risk assessment of prochloraz and its metabolite 2,4,6-trichlorophenol (2,4,6-TCP) in apple under different treatment concentrations were investigated using a GC-ECD method. The derivatization percent of prochloraz to 2,4,6-TCP was stable and complete. The recoveries of prochloraz and 2,4,6-TCP were 82.9%-114.4%, and the coefficients of variation (CV) were 0.7%-8.6% for the whole fruit, apple pulp, and apple peel samples. Under the application of 2 °C 2.0 g/L, 2 °C 1.0 g/L, 20 °C 2.0 g/L, and 20 °C 1.0 g/L treatment, the half-life for the degradation of prochloraz was 57.8-86.6 d in the whole fruit and apple peel, and the prochloraz concentration in the apple pulp increased gradually until a peak (0.72 mg·kg-1) was reached. The concentration of 2,4,6-TCP was below 0.1 mg·kg-1 in four treatment conditions and not detected (

Assuntos
Clorofenóis/análise , Fungicidas Industriais/análise , Imidazóis/análise , Malus/química , Clorofenóis/farmacologia , Fungicidas Industriais/farmacologia , Meia-Vida , Imidazóis/farmacologia , Malus/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Temperatura
7.
Chemosphere ; 171: 609-616, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28056447

RESUMO

The growing concern worldwide regarding the presence of emerging contaminants in biosolids calls for a better understanding of how different treatment technologies at water resource recovery facilities (WRRFs) can influence concentrations prior to biosolids land application. This study focuses on the influence of solids treatment via the Cambi Thermal Hydrolysis Process™ in conjunction with anaerobic digestion (TH-AD) on concentrations of triclosan (TCS), triclocarban (TCC), and their transformation products in biosolids and sludges. Concentrations of the target analytes in biosolids from the TH-AD process (Class A), sludges from the individual TH-AD treatment steps, and limed biosolids (Class B) from the same WRRF were compared. TCC concentrations were significantly lower in Class A biosolids than those in the Class B product - a removal that occurred during thermal hydrolysis. Concentrations of TCS, methyl triclosan, and 2,4-dichlorophenol, conversely, increased during anaerobic digestion, leading to significantly higher concentrations of these compounds in Class A biosolids when compared to Class B biosolids. Implementation of the TH-AD process had mixed effect on contaminant concentrations.


Assuntos
Carbanilidas/análise , Clorofenóis/análise , Triclosan/análise , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Compostos de Cálcio , Carbanilidas/química , Carbanilidas/metabolismo , Clorofenóis/química , Clorofenóis/metabolismo , Temperatura Alta , Hidrólise , Óxidos , Triclosan/análogos & derivados , Triclosan/química , Triclosan/metabolismo , Águas Residuárias
8.
J Chromatogr Sci ; 53(9): 1504-19, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25944091

RESUMO

Solid-liquid extraction, ultrasonic-assisted extraction and matrix solid-phase dispersion (MSPD) were optimized and compared in terms of recoveries for the simultaneous extraction of indole (IND) and 2,4-dichlorophenol (DCP) from catfish samples and for the extraction of IND alone from potato samples. Applying high-performance liquid chromatography (HPLC-DAD) procedure using mobile phase of methanol : water (65 : 35) at 280 nm, MSPD was the method of choice for the extraction of IND and DCP from catfish and, also, for IND from potato. The extraction recoveries of MSPD were in the range (97.9-99.7%) and (99.8-100.6%); for IND and DCP, respectively, in catfish samples and (98.4-99.7%) for IND alone in potato samples. Solid-phase extraction (SPE) was chosen the method of choice for the extraction of DCP from fish farms water samples after optimization and comparison with direct sample injection and extraction recoveries were in the range (97.9-100.3%). Kinetics were further studied to follow each of production of IND in catfish during storage at different temperatures and uptake of DCP by tilapia in fish farms water samples using MSPD-HPLC and SPE-HPLC, respectively.


Assuntos
Fracionamento Químico/métodos , Clorofenóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Indóis/isolamento & purificação , Animais , Peixes-Gato , Clorofenóis/análise , Clorofenóis/farmacocinética , Contaminação de Alimentos/análise , Indóis/análise , Indóis/farmacocinética , Cinética , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Solanum tuberosum/química
9.
Biosens Bioelectron ; 24(10): 3084-90, 2009 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-19423328

RESUMO

A biosensor for the monitoring of phenolic compounds based on a new protein named POX(1B) purified from garlic which demonstrates similar biochemical properties to peroxidase is investigated. The enzyme was immobilized into chitosan microspheres with covalent link. The properties of the biosensor were analyzed with Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and cyclic voltammetry (CV). FT-IR demonstrates the covalent attachment of POX(1B) into chitosan and SEM shows high dispersion of the POX(1B) into the chitosan microspheres. The redox potential of POX(1B) in chitosan is 147 mV vs. SCE, which is much higher than reported works using HRP, demonstrating excellent direct electrochemical behaviour of the POX(1B). The electrocatalytic activity of the obtained biosensor towards chlorophenols derivatives in a large range from 10 pM to 10 microM was demonstrated. The mediator free POX(1B)-based biosensor exhibited high sensitivity towards 2,6-dichlorophenol, 4-chlorophenol and pentachlorophenol. A detection limit of 1 pM in the case of 4-chlorophenol was demonstrated with kinetic constant K(m,app) of 0.42 microM with high rapidity of electrochemical response of the biosensor of 1 s.


Assuntos
Técnicas Biossensoriais/métodos , Clorofenóis/análise , Monitoramento Ambiental/métodos , Peroxidase , Poluentes Químicos da Água/análise , Técnicas Biossensoriais/estatística & dados numéricos , Quitosana , Técnicas Eletroquímicas , Monitoramento Ambiental/estatística & dados numéricos , Enzimas Imobilizadas , Alho/enzimologia , Microscopia Eletrônica de Varredura , Microesferas , Oxirredução , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Chromatogr A ; 972(2): 205-9, 2002 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-12416878

RESUMO

Chlorophenols in water were sorbed onto sodium dodecylsulfate (SDS)-alumina (gamma-form) admicelles. The extent of sorption increased with increasing amount of SDS and decreasing solution pH. Conditions for good recovery were obtained when 100 mg SDS and 1.5 g alumina was used at pH 2. However, the yield decreased with a further increase in the SDS concentration due to the formation of normal SDS micelles. The extent of sorption also increased with increasing hydrophobicity of the chlorophenol, indicating that hydrophobic interactions predominate for the collection of analytes. When a cartridge column filled with admicelles was used, >90% of tetrachlorophenol and pentachlorophenol in 200 ml of water samples were rapidly recovered. The sorbed analytes were eluted with 1 ml acetonitrile. The accuracy and precision of the present method were demonstrated for the HPLC analysis with ultraviolet (290 nm) detection of microg l(-1) levels of tetrachlorophenol and pentachlorophenol in river water samples.


Assuntos
Óxido de Alumínio/química , Clorofenóis/análise , Cromatografia Líquida de Alta Pressão/métodos , Dodecilsulfato de Sódio/química , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Micelas , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta
12.
Sci Total Environ ; 78: 89-98, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2717929

RESUMO

Six chlorophenolic substances were photochemically converted by illumination with xenon light. The AOX (adsorbable organic halogens) contents were determined after illumination for various periods. Pure chlorinated phenolic substances were readily detected by AOX. Both adsorbable and non-adsorbable chlorinated products were formed. Chloride analysis indicated that most (if not all) of the non-adsorbable products consisted of chloride ions. Microtox, a bacterial bioluminescence test, was used as a screening test for toxic properties of the photolysis products. Products from 2,4,6-trichlorophenol were more toxic than the original substance. Other compounds tested had less toxic products as measured by their combined effect on the Microtox system. Products of 2,4-dichlorophenol, 2,3,4-trichlorophenol, 4,5,6-trichloroguaiacol and 2,3,4,5-tetrachlorophenol did not seem to contribute to the combined toxic properties after partial photolysis of the parent compound. Pentachlorophenol was converted into products which had substantial effects on the Microtox system.


Assuntos
Clorofenóis/farmacologia , Poluentes Químicos da Água , Poluentes da Água , Cloretos/análise , Clorofenóis/análise , Clorofenóis/efeitos da radiação , Avaliação Pré-Clínica de Medicamentos/métodos , Medições Luminescentes , Photobacterium/efeitos dos fármacos , Fotólise
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