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1.
Bioorg Chem ; 130: 106268, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36399863

RESUMO

The phytoconstituents of the fraction with hemostatic activity of the 70% aqueous ethanol extract of Ypsilandra thibetica Franch. were investigated. As a result, fourteen previously unreported spirostanol saponins, ypsilandrosides Z1-Z14, and nine known analogues were isolated and characterized by MS, NMR, and chemical methods. Among them, ypsilandrosides Z1-Z4 (1-4) have a rare 12-O-ß-d-glucopyranosyl group, while ypsilandrosides Z5-Z8 (5-8) possess a rare double bond between C-4 and C-5, and a hydroxyl or carbonyl located at the C-6. All isolates were further tested for their hemostatic activity. The results suggested that five spirostanol tetraglycosides show favorable inducing platelet aggregation activities. Among them, ypsilandroside G (16) displayed significant inducing platelet aggregation activity with an EC50 value of 57.17 µM. Furthermore, the preliminary structure-activity relationship of these spirostanol glycosides' hemostatic activity was discussed.


Assuntos
Glicosídeos , Hemostáticos , Melanthiaceae , Espirostanos , Glicosídeos/farmacologia , Glicosídeos/química , Hemostáticos/farmacologia , Espectroscopia de Ressonância Magnética , Melanthiaceae/química , Espirostanos/química
2.
Plant Biotechnol J ; 20(6): 1098-1109, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35179286

RESUMO

Fluorescent tagging protein localization (FTPL) and bimolecular fluorescence complementation (BiFC) are popular tools for in vivo analyses of the subcellular localizations of proteins and protein-protein interactions in plant cells. The efficiency of fluorescent fusion protein (FFP) expression analyses is typically impaired when the FFP genes are co-transformed on separate plasmids compared to when all are cloned and transformed in a single vector. Functional genomics applications using FFPs such as a gene family studies also often require the generation of multiple plasmids. Here, to address these needs, we developed an efficient, modular all-in-one (Aio) FFP (AioFFP) vector toolbox, including a set of fluorescently labelled organelle markers, FTPL and BiFC plasmids and associated binary vectors. This toolbox uses Gibson assembly (GA) and incorporates multiple unique nucleotide sequences (UNSs) to facilitate efficient gene cloning. In brief, this system enables convenient cloning of a target gene into various FFP vectors or the insertion of two or more target genes into the same FFP vector in a single-tube GA reaction. This system also enables integration of organelle marker genes or fluorescently fused target gene expression units into a single transient expression plasmid or binary vector. We validated the AioFFP system by testing genes encoding proteins known to be functional in FTPL and BiFC assays. In addition, we performed a high-throughput assessment of the accurate subcellular localizations of an uncharacterized rice CBSX protein subfamily. This modular UNS-guided GA-mediated AioFFP vector toolkit is cost-effective, easy to use and will promote functional genomics research in plants.


Assuntos
Vetores Genéticos , Plantas , Clonagem Molecular , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Células Vegetais/metabolismo , Plantas/genética , Plasmídeos/genética , Proteínas/genética
3.
Neuroimmunomodulation ; 29(1): 55-62, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34515176

RESUMO

INTRODUCTION: LncRNA rhabdomyosarcoma 2-associated transcript (RMST) serves as a key regulator in neural stem cell fate and is involved in the progression of different neurological diseases. In this research, the serum level and clinical value of RMST in Parkinson's disease (PD) patients were detected, and the underlying mechanism was explored. METHODS: Ninety-nine PD patients and 93 healthy individuals were collected for clinical experiments. SH-SY5Y cells were treated with the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+) to establish PD cell models. qRT-PCR was used for the detection of mRNA levels. CCK-8 and flow cytometry were used to detect neuronal viability and apoptosis. The target relationship of RMST with miR-15a-5p was confirmed applying luciferase reporter assay. RESULTS: RMST was present at high levels in both serum of PD patients and PD cell models. Serum RMST had a certain clinical value for the diagnosis of PD with the AUC of 0.892 at a cutoff value of 1.225. Serum RMST was positively associated with the levels of TNF-α (r = 0.421, p < 0.001) and IL-1ß (r = 0.567, p < 0.001) in PD patients. Knockdown of RMST alleviated the apoptosis and inflammatory response of SH-SY5Y cells induced by MPP+. miR-150-5p was the target gene of RMST and less expressed in the clinical serum samples and PD cell models. CONCLUSION: Serum RMST serves as a promising biomarker for the diagnosis of PD. RMST downregulation may regulate the occurrence and development of PD through inhibiting neuron cell apoptosis and the release of inflammatory cytokines via targeting miR-150-5p.


Assuntos
MicroRNAs , Doença de Parkinson , RNA Longo não Codificante , Apoptose/genética , Linhagem Celular Tumoral , Humanos , MicroRNAs/genética , Doença de Parkinson/genética , RNA Longo não Codificante/genética
4.
Int J Mol Sci ; 23(16)2022 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-36012716

RESUMO

Tiller angle is an important trait that determines plant architecture and yield in cereal crops. Tiller angle is partially controlled during gravistimulation by the dynamic re-allocation of LAZY1 (LA1) protein between the nucleus and plasma membrane, but the underlying mechanism remains unclear. In this study, we identified and characterized a new allele of LA1 based on analysis of a rice (Oryza sativa L.) spreading-tiller mutant la1G74V, which harbors a non-synonymous mutation in the predicted transmembrane (TM) domain-encoding region of this gene. The mutation causes complete loss of shoot gravitropism, leading to prostrate growth of plants. Our results showed that LA1 localizes not only to the nucleus and plasma membrane but also to the endoplasmic reticulum. Removal of the TM domain in LA1 showed spreading-tiller phenotype of plants similar to la1G74V but did not affect the plasma membrane localization; thus, making it distinct from its ortholog ZmLA1 in Zea mays. Therefore, we propose that the TM domain is indispensable for the biological function of LA1, but this domain does not determine the localization of the protein to the plasma membrane. Our study provides new insights into the LA1-mediated regulation of shoot gravitropism.


Assuntos
Gravitropismo , Oryza , Aminoácidos/metabolismo , Regulação da Expressão Gênica de Plantas , Gravitropismo/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Brotos de Planta/metabolismo
5.
Anal Bioanal Chem ; 412(30): 8339-8350, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33029671

RESUMO

In this study, a novel fluorescent labeling reagent 2-(9-acridone)-ethyl chloroformate (AEC-Cl) was designed, synthesized and applied for the determination of free amino acids by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The free amino acids were rapidly and efficiently labeled by AEC-Cl in the presence of basic catalyst (pH 9.0) within 5 min at room temperature (25 °C). The derivatives exhibited excellent stability and fluorescence properties, with maximum excitation and emission wavelengths at 268 nm and 438 nm, respectively. Derivatives of 22 kinds of natural amino acids were completely separated by gradient elution on a Hypersil ODS C18 column. Under the optimal conditions, the calibration curves exhibited excellent linear responses, with correlation coefficients of R2 > 0.9994. The detection and quantification limits were in the range of 0.61-2.67 µg kg-1 and 2.07-8.35 µg kg-1, respectively. Therefore, AEC-Cl was successfully applied for the detection of trace levels of free amino acids in honey samples. Graphical abstract A novel fluorescent labeling reagent was applied for the determination of free amino acids in honey by high-performance liquid chromatography with a fluorescence detector.


Assuntos
Aminoácidos/análise , Cromatografia Líquida de Alta Pressão/métodos , Corantes Fluorescentes/química , Mel/análise , Espectrometria de Fluorescência/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Limite de Detecção , Reprodutibilidade dos Testes
6.
Plant Biotechnol J ; 17(8): 1657-1669, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30734457

RESUMO

Multi-functional microRNAs (miRNAs) are emerging as key modulators of plant-pathogen interactions. Although the involvement of some miRNAs in plant-insect interactions has been revealed, the underlying mechanisms are still elusive. The brown planthopper (BPH) is the most notorious rice (Oryza sativa)-specific insect that causes severe yield losses each year and requires urgent biological control. To reveal the miRNAs involved in rice-BPH interactions, we performed miRNA sequencing and identified BPH-responsive OsmiR396. Sequestering OsmiR396 by overexpressing target mimicry (MIM396) in three genetic backgrounds indicated that OsmiR396 negatively regulated BPH resistance. Overexpression of one BPH-responsive target gene of OsmiR396, growth regulating factor 8 (OsGRF8), showed resistance to BPH. Furthermore, the flavonoid contents increased in both the OsmiR396-sequestered and the OsGRF8 overexpressing plants. By analysing 39 natural rice varieties, the elevated flavonoid contents were found to correlate with enhanced BPH resistance. Artificial applications of flavonoids to wild type (WT) plants also increased resistance to BPH. A BPH-responsive flavanone 3-hydroxylase (OsF3H) gene in the flavonoid biosynthetic pathway was proved to be directly regulated by OsGRF8. A genetic functional analysis of OsF3H revealed its positive role in mediating both the flavonoid contents and BPH resistance. And analysis of the genetic correlation between OsmiR396 and OsF3H showed that down-regulation of OsF3H complemented the BPH resistance characteristic and simultaneously decreased the flavonoid contents of the MIM396 plants. Thus, we revealed a new BPH resistance mechanism mediated by the OsmiR396-OsGRF8-OsF3H-flavonoid pathway. Our study suggests potential applications of miRNAs in BPH resistance breeding.


Assuntos
Flavonoides , Hemípteros , MicroRNAs/genética , Oryza/genética , Animais , Regulação para Baixo , Herbivoria
7.
J Sep Sci ; 40(12): 2528-2540, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28371096

RESUMO

A rapid, sensitive, and selective precolumn derivatization method for the simultaneous determination of eight thiophenols using 3-(2-bromoacetamido)-N-(9-ethyl-9H)-carbazol as a labeling reagent by high-performance liquid chromatography with fluorescence detection has been developed. The labeling reagent reacted with thiophenols at 50°C for 50 min in aqueous acetonitrile in the presence of borate buffer (0.10 mol/L, pH 11.2) to give high yields of thiophenol derivatives. The derivatives were identified by online postcolumn mass spectrometry. The collision-induced dissociation spectra for thiophenol derivatives gave the corresponding specific fragment ions at m/z 251.3, 223.3, 210.9, 195.8, and 181.9. At the same time, derivatives exhibited intense fluorescence with an excitation maximum at λex = 276 nm and an emission maximum at λem = 385 nm. Excellent linear responses were observed for all analytes over the range of 0.033-6.66 µmol/L with correlation coefficients of more than 0.9997. Detection limits were in the range of 0.94-5.77 µg/L with relative standard deviations of less than 4.54%. The feasibility of derivatization allowed the development of a rapid and highly sensitive method for the quantitative analysis of trace levels of thiophenols from some rubber products. The average recoveries (n = 3) were in the range of 87.21-101.12%.

8.
J Agric Food Chem ; 72(8): 4426-4432, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38353981

RESUMO

A pair of positively charged stable isotope labeling (SIL) agents, (4-carbonochloridoylphenyl)-trimethylazanium iodide (d0-CCPTA) and d6-CCPTA, were designed and synthesized. These agents were employed in the precolumn labeling of advanced glycation end products (AGEs) within 5 min under mild conditions. Through derivatization, the mass spectrometry response of the AGEs was enhanced by approximately 2 orders of magnitude. The detection and quantitation limits were in the ranges of 3.1-7.1 and 10.0-23.7 ng/kg, respectively. The recoveries were in the range of 90.1-94.3%, and the matrix effect ranged from -6.6 to -3.5%. CCPTA produced "CCPTA-specific production ions", and all analytes were analyzed by common multiple reaction monitoring (MRM) parameters. The common MRM parameters were applied to the semitarget analysis of 41 types of AGE candidates in the absence of standards, with 13 AGEs identified.


Assuntos
Produtos Finais de Glicação Avançada , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Marcação por Isótopo , Padrões de Referência
9.
Food Chem ; 408: 135240, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36549157

RESUMO

Two pairs of stable isotope labeling (SIL) agents, (4-carboxyphenyl)trimethylammonium iodide (d0-CPTA) and its deuterated counterpart d3-CPTA, 1-methyl-nicotinamide iodide (d0-MNA) and its deuterated counterpart d3-MNA, were designed and synthesized. Their mass spectrometry (MS) sensitivity enhancement effect was studied and compared with commercial dansyl chloride to provide inspiration for labeling agent design. CPTA with quaternary ammonium group showed much higher MS sensitivity enhancement effect and was applied to the SIL analysis of alkylamines in food and food packaging materials. The matrix effect was minimized due to the SIL strategy and the permanent charge of the CPTA. The limits of detection (LODs) were in the range of 2.9-5.1 ng/L, and the limits of quantitation (LOQs) were in the range of 9.6-16.8 ng/L. The recoveries ranged from 91.2 % to 97.1 % with relative standard deviations of less than 6.6 %, and the matrix effect ranged from -1.8 % to -4.9 %.


Assuntos
Embalagem de Alimentos , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Marcação por Isótopo/métodos , Iodetos , Cromatografia Líquida de Alta Pressão/métodos
10.
Nat Prod Bioprospect ; 12(1): 17, 2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35508749

RESUMO

Phytochemical reinvestigation on the whole plants of Ypsilandra thibetica obtained four new spirostanol glycosides, named ypsilandrosides U-X (1-4), and one new cholestanol glycoside, named ypsilandroside Y (5). Their structures have been established by extensive spectroscopic data and chemical methods. Among them, compound 4 is a rare spirostanol glycoside which possesses a novel 5(6 → 7) abeo-steroidal aglycone, while compound 1 is a first spirostanol bisdesmoside attached to C-3 and C-12, respectively, isolated from the genus Ypsilandra. The induced platelet aggregation activity of the isolates was tested.

11.
J Inflamm Res ; 14: 4567-4574, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34526802

RESUMO

INTRODUCTION: Sepsis is a heterogeneous syndrome with a life-long threat caused by infection. This study aimed to investigate the clinical function of miR-940 and its influence on cardiomyocyte models. METHODS: The relative expression of miR-940 was assessed by qRT-PCR and the roles in the clinical diagnosis of miR-940 were revealed by the ROC curve. The relationship between miR-940 and clinical parameters was validated by Pearson analysis. The sepsis rat models were established by treatment with cecal ligation and perforation (CLP) and clinical items including left ventricular systolic pressure (LVSP), left ventricular and end-diastolic pressure (LVEDP), maximum rate of increase/decrease in left ventricular blood pressure (± dp/dtmax) as well as troponin (cTnl), creatine kinase isoenzyme (CK-MB), TNF-α, IL-1ß, and IL-6 were detected. RESULTS: The finding of qRT-PCR accentuated that the relative expression of miR-940 was significantly decreased in sepsis patients and CLP-stimulated models. The ROC curve proposed that miR-940 could be a satisfactory diagnostic biomarker for sepsis patients. Pearson analysis reinforced the expression of miR-940 was negatively associated with the PCT, WBC, CRP, Scr, SOFA score, and APACHE II score. The outcome of CLP-steered rat verified that overexpression of miR-940 inhibited the detrimental effects of CLP on myocardial dysfunction and inflammation reactions. CONCLUSION: The downregulation of miR-940 was reported and it might be an underlying diagnostic marker in sepsis patients. Overexpression of miR-940 protected myocardial function from damage and inflammation induced by CLP.

12.
J Agric Food Chem ; 68(33): 9024-9031, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32697581

RESUMO

A new permanently positively charged stable isotope labeling (SIL) agent pair, 4-(((2,5-dioxopyrrolidin-1-yl)oxy)carbonyl)-N,N,N-trimethylbenzenaminium iodide(DPTBA) and its deuterated counterpart d3-DPTBA, was designed and synthesized. The SIL agents were applied to the liquid chromatography-tandem mass spectrometry analysis of alkylphenols. Light labeled standards and heavy labeled samples were mixed and analyzed simultaneously. Matrix effect which mainly occurred during the ionization process was minimized because of the identical ionization processes between samples and standards. Meanwhile, derivatization made alkylphenols be positively charged, and thus the sensitivity was enhanced. The limits of detection were in the range of 1.5-1.8 ng/L, and the limits of quantitation were in the range of 4.8-6.1 ng/L. The developed method was applied to analyze alkylphenols migrated from plastics to edible oils. The recoveries for all analytes were in the range of 88.6-95.3%, while the matrix effects for all analytes were in the range of 96.2-99.6%.


Assuntos
Embalagem de Alimentos/instrumentação , Marcação por Isótopo/métodos , Fenóis/química , Óleos de Plantas/análise , Plásticos/química , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Espectrometria de Massas
13.
J Agric Food Chem ; 68(11): 3663-3669, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32096983

RESUMO

Hexadecyl trimethylammonium bromide (CTAB) micelles were applied in the synthesis of covalent organic frameworks (COFs) for the first time to achieve the synthesis of 3D COF from 2D materials. Benzidine, one raw material for COF, was enclosed in the CTAB micelles because of the hydrophobic effect, and thus the target COF, which can be formed immediately with the aid of p-toluenesulfonic acid, grew in a micelle guided 3D form. The synthesized 3D COF showed a flower-like structure, whereas the COF synthesized without CTAB showed a smooth structure. The diameter of the 3D COFs showed direct correlations with CTAB concentrations. Moreover, the CTAB modified COF also showed a dramatically improved fluorescence property in comparison with that of normal COFs. The synthesized 3D COF showed good adsorption performance for UV filters and alkylphenols with recoveries ranged from 90.2% to 99.8%, and it also showed good fluorescence response for Pb2+. The utility of CTAB modified COF was verified in the enrichment of UV filters and alkylphenols from food packaging material migrants.


Assuntos
Estruturas Metalorgânicas , Migrantes , Adsorção , Embalagem de Alimentos , Humanos , Tensoativos
14.
Anal Chim Acta ; 1055: 44-55, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-30782369

RESUMO

Chemical isotope labelling in combination with high-performance liquid chromatography-tandem mass spectrometry (CIL-HPLC-MS/MS) is a powerful method for quantitative profiling of targeted molecules. In the current work, we successfully developed a novel CIL-HPLC-MS/MS method for quantitative profiling of residual organophosphorus thioester pesticides (OPTPs) in agricultural products through the determination of the cleavage products of thiol (CP-thiol) compounds. In this method, we synthesized a novel pair of CIL reagents, i.e., N-(4-(carbazole-9-yl)-phenyl)-N-maleimide (NCPM-d0) and its deuterated analogue NCPM-d2, both of which contain a maleimide moiety as the reactive group and an isotope tag to sensitively label CP-thiol compounds. NCPM-d0 was used to label CP-thiol compounds cleaved from OPTPs in the investigated agricultural product samples, and NCPM-d2 was used to label CP-thiol compounds cleaved from OPTPs in the standard substance-spiked organic agricultural product samples. The heavily labelled derivatives were used as the internal standards (ISs) to compensate for the matrix effects during MS analysis. The NCPM-d0- and NCPM-d2-labelled derivatives generated two characteristic product ions (PIs) at m/z 372.5 and 374.5 under collision induced dissociation, respectively, which are used to establish the multiple reaction monitoring (MRM) mode-based detection. The precursor ions of NCPM-d0 and NCPM-d2 labelled derivatives of CP-thiol compounds were deduced according to the structures of the OPTPs. The peak pairs with a fixed mass difference and similar retention times were assigned as potential CP-thiol candidates for the identification of the corresponding OPTPs. Using the proposed method, we successfully determined seven residual OPTPs in agricultural product samples. Taken together, the presented method was demonstrated to be a promising new technique in the quantitation of OPTPs in agricultural product samples with high reliability.


Assuntos
Agricultura , Cromatografia Líquida de Alta Pressão/instrumentação , Ésteres/química , Compostos Organofosforados/análise , Compostos Organofosforados/química , Seringas , Espectrometria de Massas em Tandem/instrumentação , Marcação por Isótopo , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/química , Reprodutibilidade dos Testes , Compostos de Sulfidrila/química
15.
Food Chem ; 277: 407-413, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30502164

RESUMO

A new cationic gemini surfactant-resorcinol/formaldehyde resin was designed and synthesized. Cationic gemini surfactant was introduced into the resorcinol/formaldehyde resin for the first time and led to the retention of negatively charged endocrine disrupting compounds (EDCs) through electrostatic interactions, hydrogen bonding and π-π interactions. The synthesized material showed good performance in the dispersive micro-solid phase extraction (D-µ-SPE) of EDCs such as alkylphenol and phenoxy acid herbicides from food packaging migrants. Extraction parameters such as pH, adsorbent dose, extraction time and salting out effect were optimized. The limits of detections were in the range of 0.5-0.8 ng/mL, and the recoveries were in the range of 90-100%. The developed method was applied to the analysis of EDCs from food contacting materials migrants with pentachlorophenol, 2,4-dichlorophenoxyacetic acid and bisphenol A detected in the concentration range of 0.2-1.2 mg/kg. It also showed great potential in the D-µ-SPE of other compounds with negative charge or high hydrophobicity.


Assuntos
Disruptores Endócrinos/análise , Contaminação de Alimentos/análise , Formaldeído/química , Resorcinóis/química , Tensoativos/química , Ácido 2,4-Diclorofenoxiacético/análise , Compostos Benzidrílicos/análise , Embalagem de Alimentos , Pentaclorofenol/análise , Fenóis/análise , Reprodutibilidade dos Testes , Microextração em Fase Sólida
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(3): 678-80, 2008 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-18536441

RESUMO

A new and sensitive method for the determination of cadmium was developed using thermospray chemical vapor generation AAS system. The sample and KBH4 solutions were introduced into two separate thermospray tubes by peristaltic pumps and then thermosprayed into a reaction tube. The aerosol of the sample and KBH4 were mixed and reacted in the reaction tube, and after gas-liquid separation in a cyclonic spray chamber, the water vapor was removed by a desolvating unit, while the analyte was transferred into the quartz T-cell and determined by AAS. This design improved the stability and sensitivity by thermospray chemical vapor sample introducing technique. The effect of several experimental parameters of the proposed system was optimized. Under the optimized experimental conditions, the detection limits of 18 ng x L(-1) with RSD of 2.1% was obtained for cadmium determination. This method has been successfully applied to the determination of cadmium in tobacco with the recoveries of 94%-103%.


Assuntos
Cádmio/análise , Nicotiana/química , Análise Espectral/métodos , Folhas de Planta/química , Análise Espectral/instrumentação , Volatilização
17.
J Chromatogr Sci ; 56(10): 941-947, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982360

RESUMO

The extraction and analysis of free fatty acids (FFAs) in the whole natural plants are reported. The aminopropyl-functionalized SBA-15 was designed to increase the efficiency of the matrix solid-phase dispersion (MSPD) extraction method. MSPD extraction was performed using to extract FFAs via acid-base interactions. The optimum parameters for the MSPD extraction were N-SBA-15 30 mg, grinding time 120 s and elution solvent methanol-HCl (6:4, v/v). After extraction, the FFAs were analyzed by HPLC with fluorescent labeling. The reaction of the labeling agent, 2-(9-oxoacridin-10(9 H)-yl) acetohydrazide, with FFAs proceeded easily and quickly (within 20 min) in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as the condensing agent. The derivatives had excellent fluorescence properties with excitation and emission wavelengths of 260 and 430 nm, respectively. Good linear correlations were observed for all FFAs, with correlation coefficients >0.996. When 20 mg of sample were used for the analysis, the detection limits at a signal-to-noise ratio of 3 were in the range 0.21-1.20 µg g-1. The FFAs in the roots, stems, leaves and peel of Trichosanthes kirilowii Maxim were determined using the developed method.


Assuntos
Ácidos Graxos/análise , Extratos Vegetais/química , Extração em Fase Sólida/métodos , Espectrometria de Fluorescência/métodos , Trichosanthes/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
18.
J Chromatogr A ; 1557: 1-8, 2018 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-29753456

RESUMO

MCM-48 mesoporous silica was functionalized with dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, a quaternary ammonium salt with a long hydrophobic chain, to prepare a new sorbent for the dispersive solid-phase extraction (DSPE) of seven endocrine disrupting compounds (EDCs) including 4-hexylphenol, 4-octylphenol, 4-nonylphenol, bisphenol A, estrone, 17ß-estradiol and estriol in water. A series of differently functionalized MCM-48 materials were also synthesized, and they served as reference materials to study the mechanism. The developed DSPE method was combined with HPLC with fluorescence detection to evaluate the adsorption performance. The results indicated that the quaternary ammonium-functionalized MCM-48 mesoporous silica can be used as ideal sorbent for EDCs in water with recoveries of higher than 95% due to the electrostatic interactions and hydrophobic effect. Hydrogen bonding and π-π interactions in other synthesized materials could lead to about 25-30% increase in recoveries, but the results for polyhydroxy compounds were still not satisfying. The quaternary ammonium-functionalized MCM-48 mesoporous silica was successfully applied to the DSPE of EDCs in real water samples. The optimum extraction conditions were sorbent amount, 15 mg; desorption time; 5 min; elution volume, 0.8 mL; sample pH 3.0; and salt addition, 5 g/L. The limits of detection were in the range of 1.2-2.6 ng/L, while the limits of quantitation were in the range of 4.3-8.3 ng/L.


Assuntos
Disruptores Endócrinos/análise , Compostos de Amônio Quaternário/química , Dióxido de Silício/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Compostos Benzidrílicos/análise , Compostos Benzidrílicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Disruptores Endócrinos/isolamento & purificação , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Fenóis/análise , Fenóis/isolamento & purificação , Porosidade , Espectrometria de Fluorescência , Eletricidade Estática , Poluentes Químicos da Água/isolamento & purificação
19.
Talanta ; 166: 255-261, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28213231

RESUMO

A new stable isotope labeling (SIL) reagent pair, 10-methyl-acridone-2-sulfonohydrazide (MASH) and its deuterated counterpart d3-MASH was synthesized and successfully applied to the analysis of perfluorinated carboxylic acids (PFCAs) in serum samples. The limits of detection (LODs) were in the range of 0.07-0.42µg/L, and the limits of quantitation (LOQs) were in the range of 0.25-1.38µg/L. Besides ionization enhancing effect, MASH also showed excellent fluorescence property. Therefore, the mass spectrometer operation cost was greatly lowered by carrying out parameter optimization experiments on HPLC which is easier to operate and maintain. The SIL strategy was confirmed to be effective in reducing matrix effect. The developed multiple-reaction monitoring (MRM) condition of PFCAs was also suitable for other carboxylic acid due to the introduction of MASH which is more prone to fragmentation than the analytes. With the MRM conditions obtained from PFCAs, fatty acids were also found in serum samples. This feature made the proposed method show powerful potential in the identification of acidic compounds in complex samples in the absence of corresponding standard.


Assuntos
Análise Química do Sangue/métodos , Ácidos Carboxílicos/sangue , Ácidos Carboxílicos/química , Halogenação , Acridonas/química , Cromatografia Líquida , Marcação por Isótopo , Limite de Detecção , Espectrometria de Massas em Tandem
20.
Talanta ; 167: 242-252, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28340717

RESUMO

A rapid, accurate and sensitive method, using the stable isotope labeling (SIL), microwave-assisted dispersive liquid-liquid micro extraction (MADLLME) and the ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), was developed and validated for the determination of hydroxyl UV Filters in environmental water samples. A pair of new isotopic tags D0-/D3-1-methylindole-3-acetic acid (D0-/D3-MIAA) is synthesized, with which a simple yet efficient pretreatment MADLLME-SIL is developed. Under the optimized conditions (80℃, 240W, 180s), the sample pretreatment including analyte extraction, pre-concentration and isotope labeling can be finished conveniently in only 9min. D0-/D3-MIAA labeling improves the chromatographic retention by strengthening the hydrophobicity and enhances the MS response for 3-4 orders of magnitude. Excellent linearity is established by the H/D ratios of 1/10-10/1 with the correlation coefficients >0.9990. The quite low detection limits (0.54-1.79ng/L) are achieved, ensuring the trace detection. This method is successfully applied to a series of environmental water samples. The recoveries (93.2%~103.5%) are significantly improved and the analysis time is largely reduced (<15min). The excellent sensitivity, accuracy, recovery, and efficiency demonstrate this MADLLME-SIL-LC-MS/MS method a superior alternative for the analysis of UV filters in water samples.


Assuntos
Hidróxidos/análise , Hidróxidos/isolamento & purificação , Limite de Detecção , Microextração em Fase Líquida/métodos , Micro-Ondas , Raios Ultravioleta , Água/química , Hidróxidos/farmacologia , Isótopos , Espectrometria de Massas em Tandem , Fatores de Tempo
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