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1.
Food Chem ; 426: 136588, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37352713

RESUMO

While the "farm to fork" strategy ticks many boxes in the sustainability agenda, it does not go far enough in addressing how we can improve crop nutraceutical quality. Here, we explored whether supplementary ultraviolet (UV) radiation exposure during growth of broccoli and Chinese cabbage can induce bioactive tryptophan- and glucosinolate-specific metabolite accumulation thereby enhancing Aryl hydrocarbon receptor (AhR) activation in human intestinal cells. By combining metabolomics analysis of both plant extracts and in vitro human colonic fermentation extracts with AhR reporter cell assay, we reveal that human colonic fermentation of UVB-exposed Chinese cabbage led to enhanced AhR activation in human intestinal cells by 23% compared to plants grown without supplementary UV. Thus, by exploring aspects beyond "from farm to fork", our study highlights a new strategy to enhance nutraceutical quality of Brassicaceae, while also providing new insights into the effects of cruciferous vegetables on human intestinal health.


Assuntos
Brassica , Verduras , Humanos , Fermentação , Receptores de Hidrocarboneto Arílico , Fazendas
2.
Food Chem ; 404(Pt A): 134545, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36252376

RESUMO

There is an increasing interest in the use of automation in plant production settings. Here, we employed a robotic platform to induce controlled mechanical stimuli (CMS) aiming to improve basil quality. Semi-targeted UHPLC-qToF-MS analysis of organic acids, amino acids, phenolic acids, and phenylpropanoids revealed changes in basil secondary metabolism under CMS, which appear to be associated with changes in taste, as revealed by different means of sensory evaluation (overall liking, check-all-that-apply, and just-about-right analysis). Further network analysis combining metabolomics and sensory data revealed novel links between plant metabolism and sensory quality. Amino acids and organic acids including maleic acid were negatively associated with basil quality, while increased levels of secondary metabolites, particularly linalool glucoside, were associated with improved basil taste. In summary, by combining metabolomics and sensory analysis we reveal the potential of automated CMS on crop production, while also providing new associations between plant metabolism and sensory quality.


Assuntos
Ocimum basilicum , Ocimum basilicum/química , Metabolômica , Produção Agrícola , Paladar , Metabolismo Secundário
3.
Cardiovasc Diabetol ; 20(1): 237, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34920733

RESUMO

BACKGROUND: Treatment with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) leads to multiple metabolic changes, reduction in glucose levels and body weight are well established. In people with type 2 diabetes, GLP-1 RAs reduce the risk of cardiovascular (CV) disease and may also potentially represent a treatment for fatty liver disease. The mechanisms behind these effects are still not fully elucidated. The aim of the study was to investigate whether treatment with liraglutide is associated with favourable metabolic changes in cases of both CV disease and fatty liver disease. METHODS: In a prespecified post-hoc analysis of a double-blind, placebo-controlled trial in 62 individuals with type 2 diabetes (GLP-1 RA liraglutide or glimepiride, both in combination with metformin), we evaluated the changes in plasma molecular lipids and polar metabolites after 18 weeks of treatment. The lipids and polar metabolites were measured by using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS). RESULTS: In total, 340 lipids and other metabolites were identified, covering 14 lipid classes, bile acids, free fatty acids, amino acids and other polar metabolites. We observed more significant changes in the metabolome following liraglutide treatment compared to with glimepiride, particularly as regards decreased levels of cholesterol esters hexocyl-ceramides, lysophosphatidylcholines, sphingolipids and phosphatidylcholines with alkyl ether structure. In the liraglutide-treated group, lipids were reduced by approximately 15% from baseline, compared to a 10% decrease in the glimepiride group. At the pathway level, the liraglutide treatment was associated with lipid, bile acid as well as glucose metabolism, while glimepiride treatment was associated with tryptophan metabolism, carbohydrate metabolism, and glycerophospholipid metabolism. CONCLUSIONS: Compared with glimepiride, liraglutide treatment led to greater changes in the circulating metabolome, particularly regarding lipid metabolism involving sphingolipids, including ceramides. Our findings are hypothesis-generating and shed light on the underlying biological mechanisms of the CV benefits observed with GLP-1 RAs in outcome studies. Further studies investigating the role of GLP-1 RAs on ceramides and CV disease including fatty liver disease are warranted. TRIAL REGISTRATION: NCT01425580.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Hipoglicemiantes/uso terapêutico , Incretinas/uso terapêutico , Lipídeos/sangue , Liraglutida/uso terapêutico , Metaboloma , Metabolômica , Compostos de Sulfonilureia/uso terapêutico , Idoso , Biomarcadores/sangue , Cromatografia Líquida de Alta Pressão , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Hipoglicemiantes/efeitos adversos , Incretinas/efeitos adversos , Lipidômica , Liraglutida/efeitos adversos , Masculino , Metformina/uso terapêutico , Pessoa de Meia-Idade , Espectrometria de Massas por Ionização por Electrospray , Compostos de Sulfonilureia/efeitos adversos , Fatores de Tempo , Resultado do Tratamento
4.
Toxicol Appl Pharmacol ; 426: 115644, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34252412

RESUMO

Per- and polyfluoroalkyl substances (PFAS) are pervasive in the environment resulting in nearly universal detection in people. Human serum PFAS concentrations are strongly associated with increased serum low-density lipoprotein cholesterol (LDL-C), and growing evidence suggests an association with serum triacylglycerides (TG). Here, we tested the hypothesis that perfluorooctanoic acid (PFOA) dysregulates liver and serum triacylglycerides in human peroxisome proliferator activated receptor α (hPPARα)-expressing mice fed an American diet. Mice were exposed to PFOA (3.5 mg/L) in drinking water for 6 weeks resulting in a serum concentration of 48 ± 9 µg/ml. In male and female hPPARα mice, PFOA increased total liver TG and TG substituted with saturated and monounsaturated fatty acids. Lack of expression of PPARα alone also increased total liver TG, and PFOA treatment had little effect on liver TG in PPARα null mice. In hPPARα mice, PFOA neither significantly increased nor decreased serum TG; however, there was a modest increase in TG associated with very low-density cholesterol particles in both sexes. Intriguingly, in female PPARα null mice, PFOA significantly increased serum TG, with a similar trend in males. PFOA also modified fatty acid and TG homeostasis-related gene expression in liver, in a hPPARα-dependent manner, but not in adipose. The results of our study and others reveal the importance of context (serum concentration and genotype) in determining the effect of PFOA on lipid homeostasis.


Assuntos
Caprilatos/toxicidade , Dieta Ocidental , Dislipidemias/induzido quimicamente , Fluorocarbonos/toxicidade , Fígado/efeitos dos fármacos , PPAR alfa/genética , Animais , Peso Corporal/efeitos dos fármacos , Dislipidemias/genética , Dislipidemias/metabolismo , Dislipidemias/patologia , Feminino , Expressão Gênica/efeitos dos fármacos , Genótipo , Lipidômica , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos Transgênicos , Tamanho do Órgão/efeitos dos fármacos , Triglicerídeos/sangue , Triglicerídeos/metabolismo , Estados Unidos
5.
Benef Microbes ; 12(1): 17-30, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33350360

RESUMO

Faecal microbiota transfer (FMT) consists of the infusion of donor faecal material into the intestine of a patient with the aim to restore a disturbed gut microbiota. In this study, it was investigated whether FMT has an effect on faecal microbial composition, its functional capacity, faecal metabolite profiles and their interactions in 16 irritable bowel syndrome (IBS) patients. Faecal samples from eight different time points before and until six months after allogenic FMT (faecal material from a healthy donor) as well as autologous FMT (own faecal material) were analysed by 16S RNA gene amplicon sequencing and gas chromatography coupled to mass spectrometry (GS-MS). The results showed that the allogenic FMT resulted in alterations in the microbial composition that were detectable up to six months, whereas after autologous FMT this was not the case. Similar results were found for the functional profiles, which were predicted from the phylogenetic sequencing data. While both allogenic FMT as well as autologous FMT did not have an effect on the faecal metabolites measured in this study, correlations between the microbial composition and the metabolites showed that the microbe-metabolite interactions seemed to be disrupted after allogenic FMT compared to autologous FMT. This shows that FMT can lead to altered interactions between the gut microbiota and its metabolites in IBS patients. Further research should investigate if and how this affects efficacy of FMT treatments.


Assuntos
Bactérias/metabolismo , Transplante de Microbiota Fecal , Síndrome do Intestino Irritável/metabolismo , Síndrome do Intestino Irritável/terapia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Fezes/química , Fezes/microbiologia , Microbioma Gastrointestinal , Humanos , Síndrome do Intestino Irritável/microbiologia , Filogenia , Resultado do Tratamento
6.
Transl Psychiatry ; 7(9): e1240, 2017 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-28949339

RESUMO

The identification of an early biomarker of psychotic disorder is important as early treatment is associated with improved patient outcome. Metabolomic and lipidomic approaches in combination with multivariate statistical analysis were applied to identify plasma alterations in children (age 11) (38 cases vs 67 controls) and adolescents (age 18) (36 cases vs 117 controls) preceeding or coincident with the development of psychotic disorder (PD) at age 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC). Overall, 179 lipids were identified at age 11, with 32 found to be significantly altered between the control and PD groups. Following correction for multiple comparisons, 8 of these lipids remained significant (lysophosphatidlycholines (LPCs) LPC(18:1), LPC(18:2), LPC(20:3); phosphatidlycholines (PCs) PC(32:2; PC(34:2), PC(36:4), PC(0-34-3) and sphingomyelin (SM) SM(d18:1/24:0)), all of which were elevated in the PD group. At age 18, 23 lipids were significantly different between the control and PD groups, although none remained significant following correction for multiple comparisons. In conclusion, the findings indicate that the lipidome is altered in the blood during childhood, long before the development of psychotic disorder. LPCs in particular are elevated in those who develop PD, indicating inflammatory abnormalities and altered phospholipid metabolism. These findings were not found at age 18, suggesting there may be ongoing alterations in the pathophysiological processes from prodrome to onset of PD.


Assuntos
Transtornos Psicóticos/sangue , Transtornos Psicóticos/diagnóstico , Adolescente , Biomarcadores/sangue , Criança , Humanos , Lipídeos/sangue , Estudos Longitudinais , Metabolômica , Análise Multivariada , Transtornos Psicóticos/metabolismo
7.
Transl Psychiatry ; 6(11): e951, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27845774

RESUMO

Psychotic patients are at high risk for developing obesity, metabolic syndrome and type 2 diabetes. These metabolic co-morbidities are hypothesized to be related to both treatment side effects as well as to metabolic changes occurring during the psychosis. Earlier metabolomics studies have shown that blood metabolite levels are predictive of insulin resistance and type 2 diabetes in the general population as well as sensitive to the effects of antipsychotics. In this study, we aimed to identify the metabolite profiles predicting future weight gain and other metabolic abnormalities in psychotic patients. We applied comprehensive metabolomics to investigate serum metabolite profiles in a prospective study setting in 36 first-episode psychosis patients during the first year of the antipsychotic treatment and 19 controls. While corroborating several earlier findings when comparing cases and controls and the effects of the antipsychotic medication, we also found that prospective weight gain in psychotic patients was associated with increased levels of triacylglycerols with low carbon number and double-bond count at baseline, that is, lipids known to be associated with increased liver fat. Our study suggests that metabolite profiles may be used to identify the psychotic patients most vulnerable to develop metabolic co-morbidities, and may point to a pharmacological approach to counteract the antipsychotic-induced weight gain.


Assuntos
Antipsicóticos/efeitos adversos , Antipsicóticos/uso terapêutico , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/induzido quimicamente , Lipídeos/sangue , Síndrome Metabólica/sangue , Síndrome Metabólica/induzido quimicamente , Metabolômica , Obesidade/sangue , Obesidade/induzido quimicamente , Transtornos Psicóticos/sangue , Transtornos Psicóticos/tratamento farmacológico , Triglicerídeos/sangue , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Masculino , Escalas de Graduação Psiquiátrica , Medição de Risco , Adulto Jovem
8.
Diabetologia ; 57(1): 167-76, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24100782

RESUMO

AIMS/HYPOTHESIS: Not all obese individuals display the metabolic disturbances commonly associated with excess fat accumulation. Mechanisms maintaining this 'metabolically healthy obesity' (MHO) are as yet unknown. We aimed to study different fat depots and transcriptional pathways in subcutaneous adipose tissue (SAT) as related to the MHO phenomenon. METHODS: Sixteen rare young adult obesity-discordant monozygotic (MZ) twin pairs (intra-pair difference (∆) in BMI ≥ 3 kg/m(2)), aged 22.8-35.8 years, were examined for detailed characteristics of metabolic health (subcutaneous, intra-abdominal and liver fat [magnetic resonance imaging/spectroscopy]), OGTT, lipids, adipokines and C-reactive protein (CRP). Affymetrix U133 Plus 2.0 chips were used to analyse transcriptomics pathways related to mitochondrial function and inflammation in SAT. RESULTS: Based on liver fat accumulation, two metabolically different subgroups emerged. In half (8/16) of the pairs (∆weight 17.1 ± 2.0 kg), the obese co-twin had significantly higher liver fat (∆718%), 78% increase in AUC insulin during OGTT and CRP, significantly more disturbance in the lipid profile and greater tendency for hypertension compared with the lean co-twin. In these obese co-twins, SAT expression of mitochondrial oxidative phosphorylation, branched-chain amino acid catabolism, fatty acid oxidation and adipocyte differentiation pathways were downregulated and chronic inflammation upregulated. In the other eight pairs (∆weight 17.4 ± 2.8 kg), the obese co-twin did not differ from the non-obese co-twin in liver fat (∆8%), insulin sensitivity, CRP, lipids, blood pressure or SAT transcriptomics. CONCLUSIONS/INTERPRETATION: Our results suggest that maintenance of high mitochondrial transcription and lack of inflammation in SAT are associated with low liver fat and MHO.


Assuntos
Peso Corporal/fisiologia , Obesidade/metabolismo , Gêmeos Monozigóticos , Tecido Adiposo/metabolismo , Adulto , Feminino , Teste de Tolerância a Glucose , Humanos , Masculino , Obesidade/sangue , Adulto Jovem
9.
Br J Cancer ; 106(1): 99-106, 2012 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-22215106

RESUMO

BACKGROUND: We have shown that a sodium ionophore monensin inhibits prostate cancer cell growth. A structurally related compound to monensin, salinomycin, was recently identified as a putative cancer stem cell inhibitor. METHODS: The growth inhibitory potential of salinomycin was studied in a panel of prostate cells. To get insights into the mechanism of action, a variety of assays such as gene expression and steroid profiling were performed in salinomycin-exposed prostate cancer cells. RESULTS: Salinomycin inhibited the growth of prostate cancer cells, but did not affect non-malignant prostate epithelial cells. Salinomycin impacted on prostate cancer stem cell functions as evidenced by reduced aldehyde dehydrogenase activity and the fraction of CD44(+) cells. Moreover, salinomycin reduced the expression of MYC, AR and ERG, induced oxidative stress as well as inhibited nuclear factor-κB activity and cell migration. Furthermore, profiling steroid metabolites revealed increased levels of oxidative stress-inducing steroids 7-ketocholesterol and aldosterone and decreased levels of antioxidative steroids progesterone and pregnenolone in salinomycin-exposed prostate cancer cells. CONCLUSION: Our results indicate that salinomycin inhibits prostate cancer cell growth and migration by reducing the expression of key prostate cancer oncogenes, inducing oxidative stress, decreasing the antioxidative capacity and cancer stem cell fraction.


Assuntos
Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Neoplasias da Próstata/patologia , Piranos/farmacologia , Aldeído Desidrogenase/antagonistas & inibidores , Western Blotting , Linhagem Celular Tumoral , Humanos , Masculino , NF-kappa B/metabolismo , Niclosamida/farmacologia , Neoplasias da Próstata/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores Androgênicos/efeitos dos fármacos , Receptores Androgênicos/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Terfenadina/farmacologia
10.
Transl Psychiatry ; 1: e57, 2011 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-22832349

RESUMO

Mild cognitive impairment (MCI) is considered as a transition phase between normal aging and Alzheimer's disease (AD). MCI confers an increased risk of developing AD, although the state is heterogeneous with several possible outcomes, including even improvement back to normal cognition. We sought to determine the serum metabolomic profiles associated with progression to and diagnosis of AD in a prospective study. At the baseline assessment, the subjects enrolled in the study were classified into three diagnostic groups: healthy controls (n=46), MCI (n=143) and AD (n=47). Among the MCI subjects, 52 progressed to AD in the follow-up. Comprehensive metabolomics approach was applied to analyze baseline serum samples and to associate the metabolite profiles with the diagnosis at baseline and in the follow-up. At baseline, AD patients were characterized by diminished ether phospholipids, phosphatidylcholines, sphingomyelins and sterols. A molecular signature comprising three metabolites was identified, which was predictive of progression to AD in the follow-up. The major contributor to the predictive model was 2,4-dihydroxybutanoic acid, which was upregulated in AD progressors (P=0.0048), indicating potential involvement of hypoxia in the early AD pathogenesis. This was supported by the pathway analysis of metabolomics data, which identified upregulation of pentose phosphate pathway in patients who later progressed to AD. Together, our findings primarily implicate hypoxia, oxidative stress, as well as membrane lipid remodeling in progression to AD. Establishment of pathogenic relevance of predictive biomarkers such as ours may not only facilitate early diagnosis, but may also help identify new therapeutic avenues.


Assuntos
Doença de Alzheimer/metabolismo , Disfunção Cognitiva/metabolismo , Progressão da Doença , Via de Pentose Fosfato/fisiologia , Idoso , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/patologia , Biomarcadores/sangue , Biomarcadores/metabolismo , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/patologia , Feminino , Seguimentos , Humanos , Masculino , Metaboloma/fisiologia , Valor Preditivo dos Testes
11.
Analyst ; 130(1): 52-8, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15614353

RESUMO

Pressurised hot water extraction-microporous membrane liquid-liquid extraction was coupled on-line with gas chromatography-mass spectrometry (PHWE-MMLLE-GC-MS) for the analysis of pesticides in grapes. MMLLE serves as a trapping step after PHWE. Water from PHWE is directed to the donor side of the membrane unit and the analytes are extracted to the acceptor solution on the other side. The role of MMLLE is to clean and concentrate the extract before on-line transfer to the GC via a sample loop and an on-column interface using partially concurrent solvent evaporation. The extraction conditions were investigated, and then the quantitative features such as linearity, limit of quantification (LOQ), extraction yield and enrichment factors. LOQs in the range 0.3-1.8 microg kg(-1) were achieved. Procymidone and tetradifon were found in the skins of the grapes. The results were in good agreement with those obtained by liquid-solid and ultrasonic extractions.


Assuntos
Contaminação de Alimentos/análise , Resíduos de Praguicidas/análise , Vitis , Autoanálise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos
12.
J Chromatogr A ; 1056(1-2): 267-71, 2004 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-15595562

RESUMO

Microporous membrane liquid-liquid extraction (MMLLE) was coupled on-line with gas chromatography for the determination of pesticides in wine. The MMLLE-GC provided to be efficient and selective and the method was linear, repeatable and sensitive. The limits of detection ranged from 0.05 to 2.3 microg/l and the limits of quantification were 0.2-7.5 microg/l for all the analytes using FID as detector. With MS detection LODs in the range 0.03-0.4 and LOQs of 0.3-3.5 microg/l were achieved. The method was applied to the determination of pesticides in several red wines of different origin.


Assuntos
Cromatografia Gasosa/métodos , Praguicidas/análise , Vinho/análise
13.
Anal Bioanal Chem ; 375(3): 389-99, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12589504

RESUMO

Pressurised hot water extraction (PHWE) was coupled on-line with microporous membrane liquid-liquid extraction (MMLLE) and gas chromatography (GC) in the analysis of polycyclic aromatic hydrocarbon (PAH) compounds in soil. The MMLLE serves as a trapping device after the PHWE. Water from PHWE is directed to the donor side of the membrane unit and the analytes are extracted to the acceptor solution on the other side of the membrane. The role of MMLLE is to clean and concentrate the extract, which is then transferred on-line to the GC via a sample loop and an on-column interface using partially concurrent solvent evaporation. Separate optimisation of MMLLE and simulations of the PHWE-MMLLE connection were carried out before the actual on-line coupling. After optimisation of the whole on-line system, the efficiencies of the PHWE-MMLLE-GC and PHWE-solid-phase trap extractions were compared. The PHWE-MMLLE-GC method allowed on-line analysis of soil samples. The method was linear, with limits of detection in the range 0.05-0.13 ng and limits of quantification 0.65-1.66 microg g(-1). Comparison of the results with those obtained by other techniques confirmed the good performance.


Assuntos
Fracionamento Químico/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Fracionamento Químico/instrumentação , Cromatografia Gasosa , Desenho de Equipamento , Sistemas On-Line , Sensibilidade e Especificidade , Solo/normas
14.
Anal Bioanal Chem ; 372(5-6): 732-6, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11941446

RESUMO

A sample pretreatment method based on microporous membrane liquid-liquid extraction (MMLLE) was developed for the subsequent gas chromatographic determination of pesticides in wine. MMLLE provided efficient and selective extraction with enrichment factors in the range 3-13. The gas chromatographic separation was carried out using on-column injection and flame ionization detection. The method was linear, repeatable and sensitive. The limits of quantification were better than 0.006 mg/L for all the analytes except for iprodione (0.37 mg/L). The method was applied to the determination of pesticides in several red wines of different origin.


Assuntos
Cromatografia Gasosa/métodos , Membranas Artificiais , Resíduos de Praguicidas/análise , Vinho/análise , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
15.
J Chromatogr A ; 916(1-2): 89-99, 2001 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-11382314

RESUMO

The influence of high electric field strength on the separation of basic analytes in non-aqueous alcohol background electrolyte (BGE) solutions was investigated. Increasing the separation voltage in capillary electrophoresis (CE) may be advantageous if the conductivity of the BGE solution is low enough to allow fast separations without excessive Joule heating or band broadening. The voltage range tested was 20-60 kV with methanol and ethanol, and 25-60 kV with propanol and butanol as solvent for BGE. The resulting electric field strengths ranged from 660 V cm(-1) to 2000 V cm(-1). Experiments were made with a special laboratory constructed CE instrument. The separation efficiency vs. voltage curve was found to vary with the alcohol BGE solution. The increase in voltage decreased the separation efficiency in the case of methanol BGE solution, but with the other BGEs a clear efficiency maximum was obtained above 30 kV. The highest separation efficiencies were achieved with propanol BGE solution, where the efficiency maximum was reached at 45 kV. However, reasonable efficiency was achieved even at 60 kV. The extent of Joule heating was determined by calculating the temperature inside the capillary and the observed plate heights were interpreted in terms of the Van Deemter equation. The decrease in the separation efficiency with higher voltage was attributed mainly to Joule heating in the case of methanol and ethanol BGE solution and to the analyte adsorption on the capillary wall with propanol and butanol BGE solutions.


Assuntos
Eletroforese Capilar/métodos , Eletricidade , Temperatura
16.
Analyst ; 126(12): 2124-7, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11814189

RESUMO

An online multidimensional liquid chromatographic system was developed for online clean-up, derivatisation and separation of biogenic amines in wines. The system consists of a cation-exchange precolumn, a derivatisation coil and an analytical column, and a column-switching valve. The entire system can be easily automated. The method proved to be quantitative and sensitive. Limits of detection were below 0.05 mg l(-1) for all amines and linearity was preserved over the tested range (0.05-15 mg l(-1)). The method was applied to the analysis of red wines of different origin.


Assuntos
Aminas Biogênicas/análise , Vinho/análise , Cromatografia Líquida/métodos
17.
J Chromatogr A ; 896(1-2): 343-9, 2000 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-11093669

RESUMO

A simple method with minimal manual sample preparation was developed for the analysis of phenols in pyrolysis oils. Sample pre-treatment was done by gel permeation chromatography (GPC), where the high-molecular-mass lignins were separated from the phenols. Multidimensional liquid chromatography (LC-LC) was used in the analysis of the phenolic fraction. The pre-column was used for sample clean-up and pre-fractionation before introduction of the phenolic fraction to the analytical column. The repeatability and linearity of the total GPC and LC-LC methods were excellent. The results were in accordance with the reference method in which the sample pre-treatment was done by precipitating the lignins with water, and the phenols were extracted with toluene and analysed by GC-MS.


Assuntos
Cromatografia em Gel/métodos , Cromatografia Líquida/métodos , Petróleo/análise , Fenóis/análise , Reprodutibilidade dos Testes
18.
Anal Chem ; 72(14): 3070-6, 2000 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-10939369

RESUMO

Pressurized hot water extraction (PHWE) was directly combined with a LC-GC system for the determination of polyaromatic hydrocarbons (PAHs) in sediment. The sediment sample was first extracted with pressurized hot water, and the analytes were adsorbed into a solid-phase trap. The trap also functioned as a LC column, which removed most of the interfering matrix components. The 780-microL LC fraction containing the analytes was directly transferred to the GC using an on-column interface. The whole PHWE-LC-GC analysis took place in a closed system, and no sample pretreatment was required. The sensitivity of the method was excellent due to the efficient concentration in the LC-GC system. Sensitivity was approximately 800 times better than in traditional systems. In addition, only a small amount of sample (10 mg) was required for the analysis. The PHWE-LC-GC method proved to be linear in the concentration range of 0.01-2 microg/g, the limits of quantification were below 0.01 microg/g for all the analytes, and the relative standard deviations were between 3 and 28%. LC cleanup and the improved sensitivity made detection with FID sufficient for the determination of analytes. The results were comparable to those obtained in an interlaboratory comparison study as well as to the results obtained with off-line SFE-GC-MS.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Cromatografia Gasosa , Cromatografia Líquida , Indicadores e Reagentes , Água
19.
Ecotoxicol Environ Saf ; 44(3): 253-8, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10581119

RESUMO

A sediment site in the Lake Jämsänvesi (municipality of Petäjävesi, Finland) contaminated by creosote was investigated to assess the possible ecotoxicological risks it may cause to benthic animals, including ones which may arise due to physical measures in remediating the site. It is suggested that polycyclic aromatic hydrocarbons (PAHs) are bioavailable to fish and other aquatic animals during exposure to contaminated water, sediment, and food. In order to assess toxicological risks of sediment contents to fish, juvenile rainbow trout (Onchorhynchus mykiss) were intraperitoneally dosed with extracts of the creosote-contaminated sediments and their elutriates. This was compared to pristine lake sediment spiked with creosote. Activity of CYP1A1 in trout liver was measured as ethoxyresorufin O-deethylase (EROD). When compared to vehicle controls and the pristine reference sediment (0.9-1.3 pmol/min/mg PMS protein), the extract of creosote-contaminated sediment of Lake Jämsänvesi induced EROD activity up 20-30 times with a dose of 100 mg/kg [total PAHs (mg)/(kg) in fish]. The rise of EROD was associated with increasing levels of PAH metabolites in bile, analyzed as 1-OH pyrene equivalents.


Assuntos
Creosoto/efeitos adversos , Citocromo P-450 CYP1A1/metabolismo , Sedimentos Geológicos/química , Poluentes Químicos da Água/efeitos adversos , Animais , Disponibilidade Biológica , Biomarcadores/análise , Creosoto/análise , Citocromo P-450 CYP1A1/efeitos dos fármacos , Infusões Parenterais , Oncorhynchus mykiss/fisiologia
20.
Chemosphere ; 38(5): 1135-44, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10028662

RESUMO

Sediment samples, divided into three layers (0-10, 10-20 and 20-30 cm), were collected from 16 sites in Lake Jämsänvesi, Central Finland. The acute toxicity of pore waters and elutriates (sediment + water 1:4 v/v) were studied by bioluminescence inhibition test and by immobilisation of water fleas (Daphnia magna Straus). Concentrations of polycyclic aromatic hydrocarbons (PAHs) in sediments and elutriates were measured by gas chromatography using flame ionization detection (GC/FID). The highest total PAH concentration was 3.3 mg/g dry weight in the sediment and up to 1.7 mg/l in the elutriate of the uppermost (0-10 cm) layer, also being the most toxic to photoluminencent bacteria and water flea. When sediment and water mix, like during dredging operations, toxic compounds may spread from the sediment to the water column and can pose on environmental risk.


Assuntos
Creosoto/química , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes do Solo/toxicidade , Animais , Bioensaio , Daphnia , Finlândia , Água Doce/química , Medições Luminescentes , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Vibrio
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