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1.
Artigo em Inglês | MEDLINE | ID: mdl-32174544

RESUMO

Pimavanserin is a new drug approved by the FDA for Parkinson's disease psychosis and other neurological disorders such as Alzheimer's disease. In this study, we developed a UPLC-MS/MS method to quantify pimavanserin disposition in the brain and its pharmacokinetics in mice. Vilazodone was used as the internal standard. Pimavanserin and IS were extracted by liquid-liquid extraction using tert-butyl methyl ether and separated using an Acquity UPLC BEH™ C18 column. The mobile phase consisted of solvent A (0.1% formic acid in acetonitrile) and B (0.1% formic acid in 20 mM ammonium acetate buffer) (A: B, 70:30 v/v) at a flow rate of 0.25 ml/min. The multiple reaction monitoring transitions were performed at m/z 428.23 â†’ 98.15 for pimavanserin and m/z 441.70 > 155.03 for the IS. The developed method was found to be sensitive, fast, and reproducible. The linearity of the method was ˃0.99 over the range of 0.1-300 ng/mL in plasma and 0.25-300 ng/g in the brain homogenate. Precision and accuracy were within the acceptance range. The method was applied to pharmacokinetics and brain uptake studies, which showed that pimavanserin penetrates the blood-brain barrier and reaches a Cmax of 21.9 ± 6.66 ng/g in 2.0 h. We also found that pimavanserin brain to plasma ratio (Kbrain/plasma) is 0.16 ± 0.05 and it is rapidly eliminated.


Assuntos
Piperidinas/metabolismo , Piperidinas/farmacocinética , Ureia/análogos & derivados , Animais , Transporte Biológico , Barreira Hematoencefálica/metabolismo , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Extração Líquido-Líquido , Camundongos , Plasma/metabolismo , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Ureia/metabolismo , Ureia/farmacocinética
2.
Phys Chem Chem Phys ; 22(8): 4574-4580, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32048659

RESUMO

The organization of multiple subcellular compartments is controlled by liquid-liquid phase separation. Phase separation of this type occurs with the emergence of interfacial tension. Aqueous two-phase systems formed by two non-ionic polymers can be used to separate and analyze biological macromolecules, cells and viruses. Phase separation in these systems may serve as the simple model of phase separation in cells also occurring in aqueous media. To better understand liquid-liquid phase separation mechanisms, interfacial tension was measured in aqueous two-phase systems formed by dextran and polyethylene glycol and by polyethylene glycol and sodium sulfate in the presence of different additives. Interfacial tension values depend on differences between the solvent properties of the coexisting phases, estimated experimentally by parameters representing dipole-dipole, ion-dipole, ion-ion, and hydrogen bonding interactions. Based on both current and literature data, we propose a mechanism for phase separation in aqueous two-phase systems. This mechanism is based on the fundamental role of intermolecular forces. Although it remains to be confirmed, it is possible that these may underlie all liquid-liquid phase separation processes in biology.


Assuntos
Biotecnologia/métodos , Extração Líquido-Líquido , Água/química , Separação Celular , Dextranos/química , Complexos Multiproteicos/química , Complexos Multiproteicos/isolamento & purificação , Polietilenoglicóis/química , Sulfatos/química , Tensão Superficial , Vírus/isolamento & purificação
3.
Artigo em Inglês | MEDLINE | ID: mdl-32109748

RESUMO

The standard approach to detect misuse with testosterone in sport is based on the determination and evaluation of the urinary steroid profile followed by the confirmation of atypical profiles using isotope ratio mass spectrometry. The detection capacity of these methods can be attenuated by confounding factors or testosterone preparations with endogenous isotopic fingerprints. An alternative detection method for misuse of an endogenous steroid in sports is the direct detection of the administered steroid ester present in most preparations. Thus unambiguous proof for doping misuse can be delivered. In this work, the sensitivity of gas chromatography coupled to a triple quadrupole with chemical ionization (GC-CI-MS/MS) is applied to detect trace levels of 10 testosterone and 2 nandrolone esters in plasma for in human doping analysis. The detection method was developed employing a liquid-liquid extraction and HPLC cleanup step before analysis on the GC-CI-MS/MS. The quantitative method was validated in a linear range of 100-2000 pg/ml and proved to be selective, reproducible and very sensitive with limits of detection as low as to 10 pg/ml. A clinical study with the administration of testosterone undecanoate in 3 volunteers was carried out and the compound was detectable up to 86 days after administration.


Assuntos
Doping nos Esportes , Cromatografia Gasosa-Espectrometria de Massas/métodos , Esteroides/sangue , Espectrometria de Massas em Tandem/métodos , Ésteres , Humanos , Modelos Lineares , Extração Líquido-Líquido , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Esteroides/química , Esteroides/isolamento & purificação , Testosterona/análogos & derivados , Testosterona/sangue
4.
Food Chem ; 314: 126098, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31954940

RESUMO

A metabolomics strategy was developed to differentiate strong aroma-type baijiu (SAB) (distilled liquor) from the Sichuan basin (SCB) and Yangtze-Huaihe River Basin (YHRB) through liquid-liquid extraction coupled with GC×GC-TOFMS. PCA effectively separated the samples from these two regions. The PLS-DA training model was excellent, with explained variation and predictive capability values of 0.988 and 0.982, respectively. As a result, the model demonstrated its ability to perfectly differentiate all the unknown SAB samples. Twenty-nine potential markers were located by variable importance in projection values, and twenty-four of them were identified and quantitated. Discrimination ability is closely correlated to the characteristic flavor compounds, such as acid, esters, furans, alcohols, sulfides and pyrazine. Most of the marker compounds were less abundant in the SCB samples than in the YHRB samples. The quantitated markers were further processed using hierarchical cluster analysis for targeted analysis, indicating that the markers had great discrimination power to differentiate the SAB samples.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Metabolômica/métodos , Odorantes/análise , China , Análise por Conglomerados , Análise de Alimentos/estatística & dados numéricos , Cromatografia Gasosa-Espectrometria de Massas/estatística & dados numéricos , Análise dos Mínimos Quadrados , Extração Líquido-Líquido , Análise de Componente Principal , Paladar , Compostos Orgânicos Voláteis/análise
5.
PLoS One ; 15(1): e0228170, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978159

RESUMO

We describe a sensitive high performance liquid chromatography (HPLC)-based method for the determination of cholesterol in brain tissue. The method does not require the derivatization of the analyte and uses separation and quantification by reversed-phase HPLC coupled to UV detection. Lipids were methanol/chloroform extracted following the method of Bligh and Dyer, and separated using isopropanol/acetonitrile/water (60/30/10, v/v/v) as mobile phase. We observed lineal detection in a wide range of concentrations, from 62.5 to 2000 ng/µL, and were able to detect a significant increase in the brain cholesterol levels between postnatal days 2 and 10 in C57BL6 mice. Based on our validation parameters, we consider this analytical method a useful tool to assess free cholesterol in rodent brain samples and cell cultures.


Assuntos
Encéfalo/metabolismo , Colesterol/análise , Cromatografia Líquida de Alta Pressão/métodos , Animais , Colesterol/isolamento & purificação , Cromatografia de Fase Reversa , Limite de Detecção , Extração Líquido-Líquido , Camundongos , Camundongos Endogâmicos C57BL , Espectrofotometria Ultravioleta
6.
Biomed Chromatogr ; 34(4): e4788, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31899545

RESUMO

The objective of this paper was to develop a preparative method for the isolation and purification of liquiritigenin and glycyrrhetic acid from Glycyrrhiza uralensis Fisch using hydrolytic extraction combined with high-speed countercurrent chromatography (HSCCC). Liquiritigenin and glycyrrhetic acid were well hydrolyzed from liquiritin and glycyrrhizic acid by hydrochloric acid, respectively. The optimal extraction conditions were obtained by single-factor and orthogonal experiments, which were 100% ethanol, 1.5 mol/L hydrochloric acid, 1:25 ratio of solid to liquid, and extracted 2 h for one time. Using the two-phase solvent system of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v), 2.1 mg liquiritigenin (the purity was 96.5% with a recovery of 87.6%) and 12.3 mg glycyrrhetic acid (the purity was 97.1% with a recovery of 74.4%) were obtained from 315-mg crude extraction by HSCCC. The retention ratio of stationary phase was 47.2%. Their structures were identified by HPLC, melting points, UV, Fourier-transform infrared, Electrospray ionization-MS, 1 H nuclear magnetic resonance (NMR), and 13 C NMR spectra. According to the antioxidant activity assays, liquiritigenin and glycyrrhetic acid had some scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl free radicals; liquiritigenin had stronger scavenging ability on hydroxyl radicals.


Assuntos
Distribuição Contracorrente/métodos , Flavanonas/isolamento & purificação , Ácido Glicirretínico/isolamento & purificação , Glycyrrhiza uralensis/química , Extração Líquido-Líquido/métodos , Antioxidantes/química , Antioxidantes/isolamento & purificação , Flavanonas/química , Ácido Glicirretínico/química , Extratos Vegetais/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-31911204

RESUMO

This study was conducted to develop a highly selective, sensitive, and validated method for quantifying metronidazole in human plasma and bile fluid. Metronidazole and metronidazole-d4 (internal standard) were extracted from 100 µL of plasma and bile fluid by liquid-liquid extraction. Liquid chromatography with a Hydrosphere C18 column (50 × 2.0 mm) was performed using 10 mM ammonium formate (pH 4.0) and acetonitrile (20:80, v/v) as the mobile phase. Triple quadrupole mass spectrometry was operated with an electrospray ionization interface in multiple reaction monitoring and positive ion modes. The calibration curves were linear for bile and plasma samples over the range of 50-20,000 ng/mL (r2 > 0.999). The intra- and inter-day coefficients of variation (CVs) for plasma ranged from 2.50% to 7.85% and 3.11% to 16.9%, respectively; for bile, the intra-and inter-run precision (CVs) ranged from 2.76% to 13.2% and 3.16% to 11.5%, respectively. The mean extraction recovery for metronidazole ranged from 76.5% to 82.1% in plasma and from 78.8% to 87.8% in bile, respectively. Our proposed analytical method was successfully applied to determine metronidazole concentrations in bile as well as in plasma at multiple time points in a patient with acute cholangitis.


Assuntos
Bile/química , Cromatografia Líquida de Alta Pressão/métodos , Metronidazol/análise , Espectrometria de Massas em Tandem/métodos , Anti-Infecciosos/análise , Anti-Infecciosos/sangue , Anti-Infecciosos/química , Anti-Infecciosos/farmacocinética , Humanos , Limite de Detecção , Modelos Lineares , Extração Líquido-Líquido , Metronidazol/sangue , Metronidazol/química , Metronidazol/farmacocinética , Reprodutibilidade dos Testes
8.
Mini Rev Med Chem ; 20(1): 24-38, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31288718

RESUMO

Tricyclic Antidepressants (TCAs) are a group of the main category of antidepressant drugs, which are commonly prescribed to treat major depressive disorder. Determination of TCA drugs is very important for clinical and forensic toxicology, especially for therapeutic drug monitoring in various biofluids. High Performance Liquid Chromatography (HPLC) is a well-established technique for this purpose. A lot of progress has been made in this field since the past 10 years. Novel extraction techniques, and novel materials for sample preparation, novel columns and novel applications of analysis of various biofluids for the determination of TCAs in combination with other drugs are some typical examples. Moreover, advances have been performed in terms of Green Analytical Chemistry principles. Herein, we aim to discuss the developed HPLC methods that were reported in the literature for the time span of 2008-2018.


Assuntos
Antidepressivos Tricíclicos/análise , Antidepressivos Tricíclicos/farmacocinética , Cromatografia Líquida de Alta Pressão/métodos , Animais , Antidepressivos Tricíclicos/isolamento & purificação , Transtorno Depressivo Maior/tratamento farmacológico , Monitoramento de Medicamentos/métodos , Humanos , Extração Líquido-Líquido/métodos , Extração em Fase Sólida/métodos
9.
J Forensic Sci ; 65(1): 288-294, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31454427

RESUMO

Lacosamide is a functionalized amino acid with antiepileptic function. Therapeutic drug monitoring (TDM) in patients for lacosamide is critical as it allows clinicians to control epileptic seizures. A single liquid-liquid extraction step was applied for the extraction of lacosamide from whole blood samples which were thereafter analyzed by GC-MS. Optimum extraction conditions were selected on the basis of experiments with various solvents at different pHs, indicating ethyl acetate at pH 12 as the most efficient parameters for the extraction of lacosamide. Method exhibited linearity from 2 to 100 µg/mL with R2  = 0.998. Accuracy and precision were evaluated at three concentrations and found to be within acceptable limits. LOD and LOQ were determined at 0.1 and 0.5 µg/mL, respectively. Lacosamide was found to be stable at storage conditions. The developed method was applied successfully in clinical samples and postmortem blood sample from an overdose case.


Assuntos
Anticonvulsivantes/sangue , Cromatografia Gasosa-Espectrometria de Massas , Lacosamida/sangue , Anticonvulsivantes/envenenamento , Monitoramento de Medicamentos , Toxicologia Forense , Humanos , Lacosamida/envenenamento , Limite de Detecção , Modelos Lineares , Extração Líquido-Líquido , Envenenamento/diagnóstico
10.
Biomed Chromatogr ; 34(2): e4750, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31743472

RESUMO

O6 -benzylguanine (O6 BG) is an inhibitor of O6 -alkylguanine-DNA alkyltransferase (AGT). It binds to AGT by transferring its benzyl moiety to the cysteine residue at the active site of the enzyme. O6 BG synergizes the cytotoxic effects of alkylating agents by halting AGT-mediated DNA repair. O6 -benzyl-8-oxoguanine (8-oxo-O6 BG) is a metabolite of O6 BG, which is an equally potent inhibitor of AGT. In this work, we report the development and validation of an LC-MS/MS method for simultaneous determination of O6 BG and 8-oxo-O6 BG in human plasma. O6 BG and 8-oxo-O6 BG along with the analog internal standard, pCl-O6 BG, were extracted from alkalinized human plasma by liquid-liquid extraction using ethyl acetate, dried under nitrogen and reconstituted in the mobile phase. Reverse-phase chromatographic separation was achieved using isocratic elution with a mobile phase containing 80% acetonitrile and 0.05% formic acid in water at a flow rate of 0.600 ml/min. Quantification was performed using multiple-reaction-monitoring mode with positive ion-spray ionization. The linear calibration ranges of the method for O6 BG and 8-oxo-O6 BG were 1.25-250 ng/ml and 5.00-1.00 × 103 ng/ml, respectively, with acceptable assay accuracy, precision, recovery and matrix factor. This method was applied to the measurement of O6 BG and 8-oxo-O6 BG in patient plasma samples from a prior phase I clinical trial.


Assuntos
Cromatografia Líquida/métodos , Guanina/análogos & derivados , Espectrometria de Massas em Tandem/métodos , Guanina/sangue , Guanina/química , Guanina/farmacocinética , Humanos , Limite de Detecção , Modelos Lineares , Extração Líquido-Líquido , Reprodutibilidade dos Testes
11.
Artigo em Inglês | MEDLINE | ID: mdl-31622183

RESUMO

Packaging may represent a source of food contamination, as different organic compounds and degradation compounds may migrate from packaging to foodstuff. For fatty foods, rectified olive oil is the common simulant, which implies time-consuming and laborious liquid-liquid extraction (LLE) procedures to isolate the contaminant(s) from the oil. Here we propose a Multisyringe Flow Injection Analysis manifold to automate this sample treatment, using the monomer 4,4´-dihydroxybiphenyl as the contaminant. The LLE procedure, using water as extractant, was fully automated. After the on-line LLE, the resulting extract was pumped through a fluorescence detector, inside which a flow-cell filled with C18 silica gel solid support was placed. The analyte was pre-concentrated on the solid support (in which the analytical signal was directly recorded), so improving the sensitivity of the system. Under optimum conditions, the method detection limit is 0.05 mg kg-1, well within the specific migration limit of 6 mg kg-1. The method developed was compared with the standard CEN test method (off-line LLE and HPLC determination) observing savings in sample and reagents of 90% and a 7-fold increase in sample throughput.


Assuntos
Automação , Compostos de Bifenilo/análise , Análise de Injeção de Fluxo , Análise de Alimentos , Contaminação de Alimentos/análise , Extração Líquido-Líquido , Embalagem de Alimentos
12.
Food Chem ; 307: 125631, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634761

RESUMO

Lutein available in the current market is derived from marigold petals. However, extensive studies showed that microalgae are rich in lutein content and potentially exploitable for its dietary and other industrial applications. In this study, microwave assisted binary phase solvent extraction method (MABS) was the novel protocol being developed and optimized to achieve maximum lutein recovery from microalgae Scenedesmus sp. biomass. Results showed that 60% potassium hydroxide solution with acetone in the ratio of 0.1 (ml/ml) was the ideal binary phase solvent composition. Empirical model developed using response surface methodology revealed highest lutein content can be recovered through MABS extraction method at 55 °C treatment temperature, 36 min in extraction time, 0.7 (mg/ml) for biomass to solvent ratio, 250 Watt microwave power and 250 rpm stirring speed. This optimized novel protocol had increased the amount of lutein recovered by 130% and shorten the overall extraction time by 3-folds.


Assuntos
Aditivos Alimentares , Extração Líquido-Líquido/métodos , Luteína/isolamento & purificação , Scenedesmus/química , Temperatura Alta , Microalgas/química , Solventes
13.
Food Chem ; 305: 125479, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505418

RESUMO

1-o-Galloylglycerol (GG) was synthesized by the enzymatic glycerolysis of propyl gallate (PG) using a food-grade lipase (Lipozyme® 435). The reaction conditions affecting the yield of GG were optimized and a yield of 76.9% ±â€¯1.2% was obtained. GG was characterized by various techniques after being separated from the reaction mixture using liquid-liquid extraction. The water solubility and hydrophilicity of GG were significantly higher than those of gallic acid (GA) and PG. The antioxidant properties, measured by the ferric reducing antioxidant power (FRAP) and hydrogen peroxide (H2O2) scavenging assays, showed that GG exhibited the highest scavenging capacity (GG > GA > PG). From the results of the 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•+) assays, GG and GA exhibited greater scavenging capacity than PG (GG = GA > PG). These results suggest that GG may be used as a water-soluble antioxidant alternative to GA for food and cosmetic applications.


Assuntos
Antioxidantes/metabolismo , Antioxidantes/farmacologia , Ácido Gálico/análogos & derivados , Glicerol/análogos & derivados , Antioxidantes/química , Ácido Gálico/química , Ácido Gálico/metabolismo , Ácido Gálico/farmacologia , Glicerol/química , Glicerol/metabolismo , Glicerol/farmacologia , Peróxido de Hidrogênio/química , Lipase/metabolismo , Extração Líquido-Líquido , Espectroscopia de Ressonância Magnética , Galato de Propila/química , Solubilidade , Temperatura
14.
Food Chem ; 309: 125748, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31699564

RESUMO

Herein, a cold-induced aqueous two-phase system (CI-ATPS)-based concurrent sample enrichment and cleanup strategy was developed for the analysis of fipronil and its metabolites in dietary samples by liquid chromatography-high resolution mass spectrometry. By optimizing the conditions in CI-ATPS, the analytes were extracted to a small volume acetonitrile-rich phase with the enrichment factor of three-folds. Additionally, the lipids could be efficiently precipitated between the lower and upper layer to complete the removal of lipids. In detection analysis, a target single ion monitoring mode was employed to enhance the detection capability of fipronil and its metabolites. Generally, this established method could detect the target analytes in dietary samples at ng/kg level. Finally, this method was validated and certificated by a proficiency test, then was also successfully applied to dietary samples in the Total Diet Study, and the results showed that 56.3% of samples were detected with fipronil or its metabolites.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Inseticidas/análise , Inseticidas/isolamento & purificação , Extração Líquido-Líquido/métodos , Espectrometria de Massas/métodos , Pirazóis/análise , Pirazóis/isolamento & purificação , Humanos , Inseticidas/metabolismo , Pirazóis/metabolismo
15.
Food Chem ; 309: 125749, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31718840

RESUMO

This work was to develop a cost-effective and sustainable method which included metal chelate ionic liquid-based aqueous two-phase flotation (IL-based ATPF) and a two-step precipitation process for purifying bromelain from pineapple. Firstly, the metal chelate IL-based ATPF with a copper chelate-functionalized thermosensitive block copolymer (L64-IDA-Cu(II)) as trapping agent was used as the primary purification to obtain the L64-IDA-Cu(II)-bromelain complex. Secondly, the two-step precipitation process based on the thermosensitive properties of the L64-IDA-Cu(II) was mainly carried out to achieve the further purification of bromelain. According to a series of optimal experiments, the enzymatic activity recovery of final bromelain was 95.22 ±â€¯0.04%, and the purification factor reached 6.56 ±â€¯0.03. The results of recycling of ILs and the trapping agent were satisfactory. Furthermore, the conclusions of comparison with other methods proved the superiority of this method. This novel recycling purification method has a goodindustrial prospect in future.


Assuntos
Ananas/química , Bromelaínas/análise , Bromelaínas/isolamento & purificação , Cobre/química , Extração Líquido-Líquido/métodos , Extratos Vegetais/isolamento & purificação , Quelantes/química , Precipitação Química , Frutas/química , Líquidos Iônicos/química , Extratos Vegetais/análise , Polímeros/química
16.
Food Chem ; 309: 125705, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31670122

RESUMO

Red-peeled huyou has a distinct red peel color due mainly to the presence of red apocarotenoid ß-citraurin as well as the increase in amount of total carotenoids. The expression level of carotenoid cleavage dioxygenase 4b1 (CCD4b1) accounted for 99.0% of total transcript abundance of CCD4s in red-peeled huyou peel and was nearly 100 times higher than that in ordinary huyou. ß-Citraurin accumulation and peel coloration was mostly favored at 15 °C but strongly inhibited at moderately high temperatures 20 °C and 25 °C. Exogenous ethylene application for 3 d had no obvious effect on ß-citraurin accumulation in red-peeled huyou but holding fruit at moderately higher temperatures (20 °C and 25 °C) for 3 d had a significant adverse effect on ß-citraurin accumulation. The expression of phytoene synthase 1 (PSY1) and CCD4b1 was higher at 10 °C and 15 °C and significantly lower at 20 °C and 25 °C. The mechanisms governing the accumulation of ß-citraurin are discussed.


Assuntos
Citrus/efeitos dos fármacos , Etilenos/farmacologia , Armazenamento de Alimentos/métodos , Carotenoides/análise , Carotenoides/isolamento & purificação , Citrus/química , Citrus/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Frutas/química , Frutas/efeitos dos fármacos , Frutas/metabolismo , Geranil-Geranildifosfato Geranil-Geraniltransferase/genética , Geranil-Geranildifosfato Geranil-Geraniltransferase/metabolismo , Extração Líquido-Líquido , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Temperatura , beta Caroteno/análogos & derivados , beta Caroteno/análise , beta Caroteno/isolamento & purificação
17.
Food Chem ; 309: 125639, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31670126

RESUMO

We developed an isotope-dilution gas chromatography/high-resolution mass spectrometry (ID-GC/HRMS) method for the accurate determination of four polycyclic aromatic hydrocarbons (PAHs) in olive oil. The clean-up steps were optimized to sufficiently remove co-extracted oil matrix using the EZ-POP NP dual-layer and NH2 solid-phase extraction (SPE) cartridges. However, the cleaned sample still contained some matrix residues, which caused a bias. When 13C-labeled PAHs were used as the internal standards instead of deuterated PAHs, the recovery results improved in both low- and high-resolution MS conditions. Furthermore, the HRMS analysis facilitated to obtain more accurate results. The accuracy and precision of the optimized ID-GC/HRMS method were validated using PAH-fortified (0.5, 3, and 6 µg/kg) olive oil. The recoveries and relative standard deviations obtained for all the PAHs/levels were 97.5-102% and ~1%, respectively. Measurement uncertainties were generally within 5% (with a 95% confidence level).


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Azeite de Oliva/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Isótopos de Carbono/química , Cromatografia Gasosa-Espectrometria de Massas/normas , Marcação por Isótopo , Limite de Detecção , Extração Líquido-Líquido , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/normas , Padrões de Referência , Extração em Fase Sólida
18.
Food Chem ; 311: 126014, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31864181

RESUMO

A method for the simultaneous determination of three commonly used coccidiostats in chicken liver was developed, comprising a multi-residue QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction step, and a liquid chromatography-ultra violet-fluorescence (HPLC-UV/FL) analysis. The QuEChERS extraction was optimized using an experimental design approach that includes a screening step to obtain the critical variables, an optimization step using multiple response surface analysis and the calculation of a desirability parameter. The optimized method was validated with fortified samples, reaching an average recovery of 91% and an overall precision of 5.5% (mean of three analytes at three levels). Limits of detection calculated on fortified samples were 20 µg kg-1 for lasalocid, 15 µg kg-1 for nicarbazin and 120 µg kg-1 for diclazuril. These values resulted at least one order of magnitude lower than the maximum allowed residue limit (MRL) of the studied coccidiostats for chicken liver.


Assuntos
Galinhas , Coccidiostáticos/análise , Lasalocida/análise , Nicarbazina/análise , Nitrilos/análise , Triazinas/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Coccidiostáticos/isolamento & purificação , Estudos de Viabilidade , Inocuidade dos Alimentos , Lasalocida/isolamento & purificação , Extração Líquido-Líquido , Fígado/química , Nicarbazina/isolamento & purificação , Nitrilos/isolamento & purificação , Aves Domésticas , Projetos de Pesquisa , Fatores de Tempo , Triazinas/isolamento & purificação
19.
Anal Chim Acta ; 1094: 1-10, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761034

RESUMO

Detection of circulating tumor DNA (ctDNA) presents several challenges due to single-nucleotide polymorphisms and large amounts of background DNA. Previously, we reported a sequence-specific DNA extraction procedure utilizing functionalized oligonucleotides called ion-tagged oligonucleotides (ITOs) and disubstituted ion-tagged oligonucleotides (DTOs). ITOs and DTOs are capable of hybridizing to complementary DNA for subsequent capture by a magnetic ionic liquid (MIL) through hydrophobic interactions, π-π stacking, and fluorophilic interactions. However, the performance of the ITOs and DTOs in complex sample matrices has not yet been evaluated. In this study, we compare the amount of KRAS DNA extracted using ITO and DTOs from saline, 2-fold diluted plasma, 10-fold diluted plasma, and 10-fold diluted blood. We demonstrate that ITO/DTO-MIL extraction is capable of selectively preconcentrating DNA from diluted plasma and blood without additional sample preparation steps. In comparison, streptavidin-coated magnetic beads were unable to selectively extract DNA from 10-fold diluted plasma and 10-fold diluted blood without additional sample clean-up steps. Significantly more DNA could be extracted from 2-fold diluted plasma and 10-fold diluted blood matrices using the DTO probes compared to the ITO probes, likely due to stronger interactions between the probe and MIL. The ability of the DTO-MIL method to selectively preconcentrate small concentrations of DNA from complex biological matrices suggests that this method could be beneficial for ctDNA analysis.


Assuntos
Biomarcadores Tumorais/sangue , DNA Tumoral Circulante/sangue , Líquidos Iônicos/química , Proteínas Proto-Oncogênicas p21(ras)/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/isolamento & purificação , DNA Tumoral Circulante/genética , DNA Tumoral Circulante/isolamento & purificação , Humanos , Extração Líquido-Líquido , Fenômenos Magnéticos , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos/química , Sondas de Oligonucleotídeos/genética , Polimorfismo de Nucleotídeo Único
20.
Anal Chim Acta ; 1094: 34-46, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761046

RESUMO

This report presents a study on the determination of total polyphenols together with metals in several samples of olive oil produced in Spain. The results provided by applying a conventional extraction method were compared against those encountered by means of the so-called Dispersive Liquid-Liquid Aerosol Phase Extraction method. The novel method is based on the dispersion of the extracting solution in the sample. To accomplish this, an aerosol is pneumatically generated and directed against the surface of the oil sample. The aerosol was generated in order to increase as much as possible the surface area of the interface between the two involved non-miscible phases. As a result, the partition equilibrium was quickly achieved. The critical variables dictating the characteristics of the obtained aerosols as well as those influencing the partition equilibrium state were studied. With the aerosol phase extraction method, the values corresponding to the total polyphenols and metals in real samples were not statistically different as compared to those obtained by the conventional liquid - liquid extraction method. The new method provided shorter extraction times and lower mass of consumed reagents than the conventional one, thus giving rise to a more environmentally friendly method. For polyphenols, calculated limits of detection and quantification were 0.48 and 1.5 mg of gallic acid kg-1, respectively. The absorbance linearity, in turn, was kept from 0 to 50 mg kg-1 (R2 = 0.998). In the case of metal and metalloid quantification, the limits of detection found with a sample digestion method ranged from 1.3 (Cu) to 291 (Na) ng mL-1. Meanwhile, because of the lower dilution factor, this parameter was one order of magnitude lower when these elements were extracted according to the new method. The new extraction method was applied to the analysis of 42 extra virgin olive oils both bottled and directly collected from the oil press, containing single cultivars or blends and produced from different areas. Fresh oils were analyzed and a preliminary study on the oil thermal degradation was also done. Dispersing the extracting solution as an aerosol into the sample can be considered a versatile method able to provide extensive oil chemical information in a rapid way what is especially important in the case of polyphenols.


Assuntos
Extração Líquido-Líquido/métodos , Espectrometria de Massas/métodos , Metais/análise , Azeite de Oliva/análise , Polifenóis/análise , Aerossóis/química , Limite de Detecção , Espanha
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