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1.
Artigo em Inglês | MEDLINE | ID: mdl-34697706

RESUMO

This paper describes an analytical approach based on solid-phase extraction (SPE) followed by analysis using liquid and gas chromatography coupled to mass spectrometry detectors for a determination of 18 organic UV filters from water samples. Extraction method parameters were optimized: 250 ml of water sample loaded on Chromabond C18 cartridges after adjustment to pH 4 and then eluted with acetonitrile. The mobile phase and the parameters of the mass spectrometer, as well as those of the ionization source, were tested to enhance detection sensitivity. During method validation, the extracted target compounds showed good recoveries (> 68%) with acceptable values in terms of repeatability (RSDr) and reproducibility (RSDR), where relative standard deviations values were lower than 20%. The validated method was applied to 10 water samples collected from different swimming pools located in Lebanon from which eight UV filters among the eighteen targets compounds were detected at concentrations ranged between 1 and 2526 µg L-1. The most detected compounds were padimate-O (OD-PABA) and octocrylene (OCR). This study represents the first available data on the occurrence of UV filter residues in Lebanese swimming pool opening hence future perspectives and insights to evaluate their degradation by-products and their toxicity on human health and marine ecosystem.

2.
J Mass Spectrom ; 56(6): e4730, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-34000760

RESUMO

Honey is one of the most valuable sweeteners consumed by humans all over the world. Consequently, it is often a target for adulteration through the addition of different sugar syrups during or after honey production, resulting in a reduction in its nutritive value. For the first time, this study analyzes honey samples of various botanical species collected from different Lebanese regions using element analyzer (EA) and liquid chromatography (LC) coupled with isotope ratio mass spectrometry (IRMS). The δ13 C of bulk honey, its protein fraction, and the main individual sugars (glucose, fructose, disaccharides, and trisaccharide) were determined, in order to characterize and evaluate the authenticity of honey consumed in Lebanon. The results showed that the δ13 C values for bulk honey and its protein range from -26.5‰ to -24.5‰ and from -26.4‰ to -24.7‰, respectively, for authentic samples. δ13 C values for samples adulterated with sugar syrups range from -11.2‰ to -25.1‰ for bulk honey and from -26.6‰ to -23.7‰ for its proteins, with a difference between bulk and protein values between -1 and -8.7‰. Using LC-C-IRMS techniques, the δ13 C of individual sugars provides additional information on the presence of undeclared sugars. We found that all authentic samples had Δδ13 Cf-g and Δδ13 C max values within the naturally occurring range of ±1‰ and ±2.1‰, respectively, while the adulterated samples fall outside the Δδ13 C ranges. The oligosaccharide peak was detected in most adulterated samples.

3.
F1000Res ; 9: 1254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33299557

RESUMO

Background: The expanding burden of diet-related non-communicable diseases in the Eastern Mediterranean Countries requires urgent public health vigilance and actions. This study aimed at establishing a database analysis of total sugar, salt and iron content in Lebanese foods, focusing on traditional dishes. Methods: The collection of food samples was done using stratified sampling techniques. These samples were classified into five strata, taking into account variation by geographical area (Mount Lebanon, Bekaa, Beirut, Tripoli, and Saida). The number of samples per governorate was estimated to be 30 according to the variability in the dishes' composition. Food samples were chemically analyzed for total sugar, salt, and iron. Results: Among all the governorates, all the tested traditional Lebanese dishes contained little total sugar. More than 60% of the samples tested were rich in sodium. The sodium content ranges were 120-720 mg/100 g in Mount Lebanon, 240-960 mg/100 g in Bekaa, 80-520 mg/100g in Beirut, 252-1952 mg/100g in Tripoli and 40-680 mg/100 g in Saida. The highest mean amount of sodium was observed in the dishes Fatayer Sabanikh and Malfouf Mehche (≥ 600 mg/100 g). Furthermore, more than 80% of the samples had poor amounts of iron in all governorates. Conclusion: This study emphasizes the need for multi-cultural education and awareness on food sources of salt and iron, and the health effects regarding high intake of salt and low intake of iron. This study is a stepping stone for further research exploring total sugar, salt and iron content of traditional dishes, as well as potential intake by individuals in the Lebanese population.


Assuntos
Dieta , Ferro , Humanos , Líbano , Valor Nutritivo , Açúcares
4.
Toxicol Rep ; 7: 1025-1031, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32913715

RESUMO

Widely used for a variety of applications, levels of dietary aluminum (Al) have seen a perpetual rise in Lebanon, leading to noticeable effects upon the human body. This study aims to estimate the rates of Al contaminated food consumption and quantify the Al present in different dietary matrices, revealing the major contributors to Al exposure for the Lebanese population. A cross-sectional study was conducted using a customized, self-reported Electronic Food Frequency Questionnaire (E-FFQ) using Curve®, targeting individuals between the ages of 18 and 64 from different Lebanese regions, distributed proportionally. The selection of food was based upon the results of the French EAT2 study. Al levels in food were analyzed using Flame Atomic Absorption Spectrometry (FAAS) after acid digestion. The E-FFQ was completed by 167 respondents. Data analysis was performed on SPSS version 25. Additionally, 97 food items were studied in 2018. Al levels had a mean of 3.56 ± 2.08 mg/kg (ranging from 0.14 to 9.37). The highest Al levels were found in vegetables, followed by sauces and condiments, candies, and ready meals. The Provisional Tolerable Weekly Intake (PTWI) of Al was set at 0.50 mg/kg body weight (60 Kg/person). Al mean Daily Dietary Exposure (DDE) was estimated to be 4341.18 µg/day, with the highest food exposure coming from lettuce, soft drinks, ice cream and tea. Al ingestion rates for the adult Lebanese population does not exceed the international established thresholds of tolerable intake (1 mg/kg/week). National recommendation should be developed to control the presence of metal for food safety purposes.

5.
Int J Mol Sci ; 21(17)2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32872422

RESUMO

Recent experimental findings suggest the involvement of the 26S proteasome, the main protease active in eukaryotic cells, in the process that leads mammalian sperm to become fully fertile, so-called capacitation. Unfortunately, its role in male gametes signaling is still far from being completely understood. For this reason, here, we realized a computational model, based on network theory, with the aim of rebuilding and exploring its signaling cascade. As a result, we found that the 26S proteasome is part of a signal transduction system that recognizes the bicarbonate ion as an input terminal and two intermediate layers of information processing. The first is under the control of the 26S proteasome and protein kinase A (PKA), which are strongly interconnected, while the latter depends on intracellular calcium concentrations. Both are active in modulating sperm function by influencing the protein phosphorylation pattern and then controlling several key events in sperm capacitation, such as membrane and cytoskeleton remodeling. Then, we found different clusters of molecules possibly involved in this pathway and connecting it to the immune system. In conclusion, this work adds a piece to the puzzle of protease and kinase crosstalk involved in the physiology of sperm cells.


Assuntos
Cálcio/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Espermatozoides/fisiologia , Animais , Bicarbonatos/metabolismo , Humanos , Masculino , Modelos Teóricos , Redes Neurais de Computação , Fosforilação , Transdução de Sinais , Capacitação Espermática
7.
Food Addit Contam Part B Surveill ; 13(2): 121-129, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32200691

RESUMO

The treatment of animals with antimicrobial products may lead to the contamination of edible tissues by their residues, which may represent a risk to human health. Therefore, this study aimed to determine the level of antimicrobial residues in food-producing animals (chicken, beef, and milk) in Lebanon. A total of 310 samples were collected and analysed using an LC-MS/MS for the determination of 48 compounds belonging to different families in order to map their compliance according to the European Commission decision 2002/657/EC. Results show that 60% of the analysed samples were not contaminated by any residue, while 12% presented a concentration higher than the MRLs for tetracyclines, sulphonamides, quinolones, and macrolides. Results revealed that chicken were the most contaminated by antimicrobial residues, when compared to beef and milk. The obtained results demonstrate the uncontrolled use of antimicrobials in some Lebanese farms and claim for better management of livestock.


Assuntos
Anti-Infecciosos/análise , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Carne/análise , Leite/química , Animais , Bovinos , Galinhas , Líbano
8.
Food Chem Toxicol ; 138: 111204, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081729

RESUMO

A new method, using liquid chromatography coupled to mass spectrometry (LC-MS/MS) for the detection of fourteen natural and synthetic hormones in muscles, was validated in other bovine matrices (liver, kidney, bile and hair) according to the Decision Commission 2002/657/EC. As result, this method demonstrates good linearity (R2 > 0.99) as well as accuracy with coefficients of variation for repeatability and reproducibility lower than 23%. Moreover, the values of decision limit (CCα) and detection capability (CCß) were determined indicating values ranging from 0.13 to 0.86 µg/kg and 0.25-1.72 µg/k for the majority of analytes. Recovery rate in the different matrices varied from 51.5 to 107%. Indeed, this method has been successfully applied to detect anabolic hormones in eighty-eight samples (muscle, liver, kidney, and bile) collected from different local slaughterhouses. Results showed that progesterone was found in 30 samples at concentrations ranging from 0.11 to 11.7 µg/kg, while testosterone was detected in 34 samples at concentrations ranging from 0.5 to 9.52 µg/kg. All bile samples contain epi-testosterone at concentration ranging from 0.89 to 280 µg/kg. These obtained data were used to calculate the estimated daily intake, hazard quotient and hazard index as exposure assessment.


Assuntos
Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem , Animais , Bile/química , Bovinos , Cabelo/química , Rim/química , Limite de Detecção , Fígado/química , Músculos/química , Progesterona/análise , Reprodutibilidade dos Testes , Medição de Risco , Sensibilidade e Especificidade , Testosterona/análise
9.
Food Addit Contam Part B Surveill ; 12(2): 81-89, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30642226

RESUMO

In Lebanon, apples are among the most consumed commodities; however, pesticide residues in apples have not been evaluated so far. Therefore, this study presents the occurrence of pesticide residues in apples produced in Lebanon during 2012-2016. A total of 212 samples were analysed for the presence of pesticides using the QuEChERS multi-residue extraction method, followed by GC-MS. Pesticide residues were not observed in 23% of the samples. Whereas pesticide residues were found in 77% of the samples, among them 61% exceeded the maximum residue limits (MRL) and 16% contained residues below the MRL. The most frequently detected pesticide residues were chlorpyrifos (n = 142), methidathion (n = 34), cypermethrin (n = 21), lambda-cyhalothrin (n = 16), myclobutanil (n = 13) and diazinon (n = 9). A preliminary long-term exposure assessment for the detected pesticides in apples showed that Hazard Quotient (HQ) was in the range of 0.1-8% of the ADI's, indicating no risk to human health.


Assuntos
Frutas/química , Malus/química , Medição de Risco , Clorpirifos/análise , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Humanos , Líbano , Concentração Máxima Permitida , Nitrilas/análise , Compostos Organotiofosforados/análise , Resíduos de Praguicidas/análise , Piretrinas/análise , Controle de Qualidade , Reprodutibilidade dos Testes
10.
J Mass Spectrom ; 53(7): 614-623, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29672996

RESUMO

Sulfonamides (SNs) are synthetic antimicrobial agents. These substances are continually introduced into the environment, and they may spread and maintain bacterial resistance in the different compartments. The chlorination of 2 SNs, namely, sulfamethazine (SMT) and sulfamethoxypyridazine (SMP), was investigated to study their reactivity with chlorine at typical concentrations for water treatment conditions. Experiments conducted in purified water show an acceleration of SMT and SMP degradation of a factor 1.5 by comparison to drinking water matrix. This difference is due to pH variation and competitive reactions between SNs and mineral and organic compounds, with chlorine in drinking water. In the presence of an excess of chlorine (6.7 µmol·L-1 ) in ultrapure water at pH 7.2, second-order degradation rate constants were equal to 4.5 × 102 M-1 ·s-1 and 5.2 × 102 M-1 ·s-1 for SMT and SMP, respectively. The structures of transformation products were investigated by liquid chromatography tandem mass spectrometry analyses with equimolar concentrations between chlorine and SNs. SO2 elimination, cyclization, and electrophilic substitutions were the main pathways of by-products formation. Moreover, the toxicity of the proposed structures was predicted by using toxicity estimation software tool program. The results indicated that most by-products may present developmental toxicity.


Assuntos
Antibacterianos/química , Cloro/química , Sulfametazina/química , Sulfametoxipiridazina/química , Poluentes Químicos da Água/química , Cromatografia Líquida de Alta Pressão , Simulação por Computador , Halogenação , Cinética , Oxirredução , Sulfametazina/toxicidade , Sulfametoxipiridazina/toxicidade , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/toxicidade , Purificação da Água
11.
Chemosphere ; 193: 329-336, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29149708

RESUMO

Kinetics of photodegradation of novel oral anticoagulants dabigatran, rivaroxaban, and apixaban were studied under simulated solar light irradiation in purified, mineral, and river waters. Dabigatran and rivaroxaban underwent direct photolysis with polychromatic quantum yields of 2.2 × 10-4 and 4.4 × 10-2, respectively. The direct photodegradation of apixaban was not observed after 19 h of irradiation. Kinetics of degradation of rivaroxaban was not impacted by the nature of the aqueous matrix while photosensitization from nitrate ions was observed for dabigatran and apixaban dissolved in a mineral water. The photosensitized reactions were limited in the tested river water (Isle River, Périgueux, France) certainly due to the hydroxyl radical scavenging effect of the dissolved organic matter. The study of photoproduct structures allowed to identify two compounds for dabigatran. One of them is the 4-aminobenzamidine while the second one is a cyclization product. In the case of rivaroxaban, as studied by very high field NMR, only one photoproduct was observed i.e. a photoisomer. Finally, seven photoproducts were clearly identified from the degradation of apixaban under simulated solar light.


Assuntos
Anticoagulantes/efeitos da radiação , Água Doce/química , Fotólise/efeitos da radiação , Luz Solar , Benzamidinas , França , Radical Hidroxila , Cinética , Pirazóis , Piridonas , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/efeitos da radiação
12.
Environ Sci Pollut Res Int ; 25(35): 34863-34872, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29192403

RESUMO

Sulfaquinoxaline (SQX) is an antimicrobial of the sulfonamide class, frequently detected at low levels in drinking and surface water as organic micropollutant. The main goal of the present study is the evaluation of SQX reactivity during chlorination and UV irradiations which are two processes mainly used in water treatment plants. The SQX transformation by chlorination and UV lights (254 nm) was investigated in purified water at common conditions used for water disinfection (pH = 7.2, temperature = 25 °C, [chlorine] = 3 mg L-1). The result shows a slow degradation of SQX during photolysis compared with chlorination process. Kinetic studies that fitted a fluence-based first-order kinetic model were used to determine the kinetic constants of SQX degradation; they were equal to 0.7 × 10-4 and 0.7 × 10-2 s-1corresponding to the half time lives of 162 and 1.64 min during photolysis and chlorination, respectively. In the second step, seven by-products were generated during a chlorination and photo-transformation of SQX and identified using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS-MS). SO2 extrusion and direct decomposition were the common degradation pathway during photolysis and chlorination. Hydroxylation and isomerization were observed during photodegradation only while electrophilic substitution was observed during chlorination process.


Assuntos
Cloro/química , Modelos Químicos , Sulfaquinoxalina/química , Poluentes Químicos da Água/química , Cromatografia Líquida , Desinfecção/métodos , Halogenação , Hidroxilação , Cinética , Processos Fotoquímicos , Fotólise , Espectrometria de Massas em Tandem , Raios Ultravioleta , Poluentes Químicos da Água/análise , Purificação da Água/métodos
13.
Artigo em Inglês | MEDLINE | ID: mdl-28869744

RESUMO

This study examines the behaviour of volatile perfluorinated carboxylic acids used as ion-pairing reagents for the separation of multiclass antimicrobial residues in honey (tetracyclines, sulphonamides, macrolides, and aminoglycosides). Heptafluorobutanoic acid and pentafluoropentanoic acid were compared as mobile phase additives at concentrations of 0-20 mmol.L-1 using reversed-phase chromatography. Our objective was to find optimal conditions that enable the separation of antimicrobials with a minimum loss in sensitivity and efficiency. The influence of ion pairing on chromatographic performance was examined. Results showed that heptafluorobutanoic acid was able to separate aminoglycosides faster and more efficiently than pentafluoropentanoic acid, but at low concentrations of heptafluorobutanoic acid between 2.5 and 5 mM, tetracyclines showed poor chromatographic efficiency. A concentration of 10 mM was found to be optimal for all studied veterinary drugs. The method was then applied to determine multiclass antimicrobial residues in honey. Based on validation data, the mean recoveries of analytes ranged between 93% and 104%, and the intermediate precisions were <21%. The decision limit (CCα) and detection capability (CCß) were in the ranges of 5-25 and 7-33 µg kg-1, respectively. The method was found to be suitable for use in analysis of veterinary drugs with a broader group of compounds found in food-producing animals.


Assuntos
Anti-Infecciosos/análise , Ácidos Carboxílicos/análise , Resíduos de Drogas/análise , Fluorcarbonetos/análise , Mel/análise , Cromatografia Líquida , Espectrometria de Massas em Tandem
14.
Sci Total Environ ; 609: 830-841, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-28783898

RESUMO

A powerful analytical method for simultaneous determination of 63 pharmaceuticals and some metabolites in aqueous samples has been developed. The list of compounds amenable to the methods includes different therapeutic classes belonging to antibiotics, stimulants, antidepressants, mucolytics, and antiparasites. The method involves concentration and clean up by an offline solid phase extraction SPE followed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS/MS). The recovery of the target compounds from water samples was most efficient on Waters Oasis HLB SPE cartridge, while acetonitrile/water (60/40) was shown to be the most suitable solvent for desorbing the compounds from SPE. In addition, acidification of samples prior to SPE was optimized to enhance the recovery of the compounds. In terms of method validation, the recoveries of analytes ranged from 68% to 134%. Repeatability and intermediate precision were <11% and 14%, respectively. The method detection limits ranged from 2.3ngL-1 to 94.3ngL-1. An optimized method was applied in a monitoring program to study the occurrence of pharmaceuticals to more than hundred samples collected from rivers, lakes, fountains, and wells overall Lebanon from April to June 2016. Caffeine, erythromycin and its degradation forms, were the most frequently detected compounds at levels reaching >10,000ngL-1 and 2000ngL-1, respectively. Moreover, bacterial analysis showed that the samples were contaminated by Escherichia coli (23%), intestinal Enterococcus (48%) and Pseudomonas aeruginosa (27%). Therefore, in order to evaluate if a correlation exists between finding antibiotics in water samples and the development of resistant-bacteria, an antimicrobial susceptibility test was conducted to the identified isolates using disk diffusion method. Multiple-antibiotic-resistant strains in both intestinal Enterococcus and E. coli were evident in many water samples, while P. aeruginosa was resistant to only one studied antibiotic.


Assuntos
Antibacterianos/análise , Farmacorresistência Bacteriana , Microbiologia da Água , Poluentes Químicos da Água/análise , Cromatografia Líquida , Enterococcus/isolamento & purificação , Escherichia coli/isolamento & purificação , Água Doce/análise , Líbano , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/isolamento & purificação , Extração em Fase Sólida , Espectrometria de Massas em Tandem
15.
Rapid Commun Mass Spectrom ; 31(13): 1103-1110, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28488287

RESUMO

RATIONALE: This paper investigates the validity of the transfer of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of veterinary medicinal products in honey and compares it with an LC/linear ion trap/Orbitrap mass spectrometry method. A descriptive statistical approach was used in order to assess whether such a transfer would succeed or fail. This approach is based on the simultaneous evaluation of the trueness and of the intermediate precision for each compound at a 95% interval of confidence of both analytical techniques. METHODS: Two grams of honey were placed in a centrifuge tube and diluted with 2.5 mL of ultra-pure water and 2.5 mL of acidified methanol with hydrochloric acid at 2 mol.mL-1 . The extract was purified with 50 mg of primary secondary amine and then analyzed using LC/MS/MS in multiple reaction monitoring (MRM) mode and LC/orbitrap high-resolution mass spectrometry in full scan mode. Both analytical techniques were compared by using the descriptive statistical approach for the determination of antimicrobial residues in honey. RESULTS: The transfer of the method showed that the Orbitrap system provides the same accurate analytical results compared with the LC/MS/MS method except for 4-epitetracycline, anhydroerythromycin A, erythromycin A enol ether, and dihydrostreptomycin. Furthermore, the LC/LTQ-Orbitrap system is capable of successfully competing with the LC/MS/MS method by additional provision of high mass resolution and mass accuracy even though it shows less sensitivity compared with the LC/MS/MS instrument. CCα levels for most analytes were 1.3 times higher by LC/MS/MS than those observed by LC/LTQ-Orbitrap. The method was assessed in terms of relative bias through analysis of a reference material provided by FAPAS (Food Analysis Performance and Assessment Scheme) and also through the control of several contaminated honey samples from local Lebanese markets. Satisfactory relative bias was below 22% except for tetracycline found in one sample that showed a higher bias at 29%. CONCLUSIONS: The LC/LTQ-Orbitrap method offers adequate performance in comparison with previously validated method on a LC/MS/MS system resulting in acceptance of the transfer of the method from LC/MS/MS to LC/LTQ-Orbitrap. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Anti-Infecciosos/análise , Cromatografia Líquida/métodos , Resíduos de Drogas/análise , Mel/análise , Espectrometria de Massas em Tandem/métodos , Limite de Detecção , Reprodutibilidade dos Testes , Drogas Veterinárias/análise
16.
Environ Sci Pollut Res Int ; 24(9): 7982-7993, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28108916

RESUMO

In this study, we aimed to investigate the kinetics and the mechanism of reaction of the fluoroquinolone antibacterial danofloxacin (DANO) by free available chlorine (FAC) during water chlorination process. Kinetic study was thus performed at pH 7.2, 20 °C in the presence of an excess of total chlorine. Under these experimental conditions, a second-order reaction rate constant (first-order relative to DANO concentration and first-order relative to FAC concentration) was evaluated to k~1446 M-1 s-1. Five degradation products were identified at different reaction times. Their structures were investigated by using fragmentations obtained at different CID collision energies in MS/MS experiments. Moreover, the toxicity of the proposed structures was predicted by using T.E.S.T. PROGRAM: The results indicated that all by-products may have a developmental toxicity. The oral rat LD50 concentration was predicted to be lower than that of DANO. Furthermore, two degradation compounds presented a concentration level for fathead minnow LC50 (96 h) lower than that of DANO and presented toxicity for the marine animals.


Assuntos
Antibacterianos , Cloro/química , Fluoroquinolonas , Poluentes Químicos da Água , Animais , Antibacterianos/química , Antibacterianos/toxicidade , Cromatografia Líquida , Simulação por Computador , Cyprinidae , Fluoroquinolonas/química , Fluoroquinolonas/toxicidade , Halogenação , Cinética , Dose Letal Mediana , Modelos Teóricos , Oxirredução , Ratos , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos
17.
Artigo em Inglês | MEDLINE | ID: mdl-27601204

RESUMO

A new, simple and fast method was developed for the determination of multi-class antibiotic residues in honey (sulfonamides, tetracyclines, macrolides, lincosamides and aminoglycosides). Separation and determination were carried out by LC-MS/MS. During sample preparation, various parameters affecting extraction efficiency were examined, including the type of solvent, pH, efficiencies of cleavage of N-glycosidic linkages by hydrochloric acid, ultrasonic extraction and its duration compared with shaking, along with dispersive SPE clean-up. Experiments with fortified samples demonstrated that 10 min of ultrasonic treatment with acidified methanol (HCl 2 M) followed by dispersive SPE clean-up with 50 mg PSA gave an effective sample preparation method for several classes of antibiotics in honey. Anhydroerythromycin A, erythromycin A enol ether and desmycosin were used as markers for the presence of erythromycin A and tylosin A in honey samples. The method was validated according to European Commission Decision (EC) No. 2002/657. The recoveries of analytes ranged from 85% to 111%. Repeatability and intra-laboratory reproducibility were < 20.6% and 26.8%, respectively. Decision limit (CCα) and detection capability (CCß) ranged from 6 to 9 µg kg-1 and from 7 to 13 µg kg-1, respectively, except for streptomycin and neomycin, which showed slightly higher CCα at 25 µg kg-1 and CCß at 34 µg kg-1. Finally, the method was applied to the honey test material 02270 through a FAPAS proficiency test (PT) for the determination of tetracyclines. PT results were obtained within a z-score range of ±2, proving that the validated method is suitable for routine analysis to ensure the quality of honey.


Assuntos
Antibacterianos/análise , Cromatografia Líquida/normas , Contaminação de Alimentos/análise , Mel/análise , Espectrometria de Massas em Tandem/normas , Drogas Veterinárias/análise , Aminoglicosídeos/análise , Animais , Abelhas/fisiologia , Controle de Medicamentos e Entorpecentes/legislação & jurisprudência , União Europeia , Humanos , Lincosamidas/análise , Macrolídeos/análise , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Sulfonamidas/análise , Tetraciclinas/análise
18.
Bull Environ Contam Toxicol ; 91(5): 503-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24008278

RESUMO

Contamination of water sources by pesticides is one of the most critical environmental problems. The present work is designed to address the occurrence of 67 pesticides in the Lebanese waters. Chemical analysis was performed by a solid-phase extraction followed by a gas chromatography-mass spectrometry using programmed temperature vaporization injection. In drinking water and groundwater samples, organochlorine and organophosphate pesticides were frequently detected with a maximal sum concentration of up to 31.8 ng L(-1). High pesticide ecotoxicological risk was noticed in many surface waters, while this risk was driven mainly by diazinon, chlorpyrifos, fenpropathrin and bifenthrin insecticides.


Assuntos
Monitoramento Ambiental , Resíduos de Praguicidas/análise , Poluentes Químicos da Água/análise , Recursos Hídricos/análise , Água Doce/química , Líbano , Compostos Organofosforados/análise , Extração em Fase Sólida , Recursos Hídricos/estatística & dados numéricos
19.
J Agric Food Chem ; 59(14): 7592-600, 2011 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-21476566

RESUMO

A fast and reliable method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by solid-phase extraction (SPE) using centrifugation has been developed and optimized. A silica-based C18 cartridge was used; parameters affecting the extraction procedure such as type and volume of the elution solvent, breakthrough volume of the percolated water sample, drying of the sorbent, and evaporation of the elute have been studied. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 1 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under optimal conditions, recoveries for the 16 U.S. EPA PAHs were between 70 and 85% and the relative standard deviation varied between 1 and 14%. Surrogate standard recoveries were similarly between 61 and 94% with a relative standard deviation between 2 and 15%. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.


Assuntos
Centrifugação/métodos , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise
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