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1.
Phys Rev Lett ; 113(2): 029802, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-25062249
2.
Mycotoxin Res ; 22(4): 197-200, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23605708

RESUMO

An effective and timesaving analytical method was developed for the determination of 12 ergot alkaloids (ergometrine, ergotamine, ergocristine, α-ergokryptine, ergosine, ergocornine, and their respective -inine isomers) in rye and rye flour. Samples were extracted with dichloromethane/ethyl acetate/methanol/aqueous ammonia (25%) (50/25/5/1, v/v/v/v), and extracts were purified using a basic alumina column. The eluate was dried in the nitrogen stream and redissolved in acetonitrile/ ammonia carbamate-buffer (0.2 g/1), (1/1, v/v), and injected into an HPLC-FLD system (λEx 330 nm, λEm 415 nm), using the same mixture as mobile phase and a Phenyl-Hexyl column. Detection limits for the individual compounds ranged from 0.01 µg/kg to 0.5 µg/kg. In sample material spiked with a mixture of these compounds at two different levels (13 µg/kg and 27 µg/kg per compound), mean (n=5) recoveries were at 101% (sr 6.4%) and 89% (sr 3.1%), respectively.

3.
Mycotoxin Res ; 21(1): 3-6, 2005 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-23605196

RESUMO

A new method for the determination of zearalenone in edible oils with size exclusion chromatography (SEC) followed by LC-MS/MS as well as HPLC-FLD was developed and validated. By using the LC-MS/MS determination no further clean up step is necessary after the SEC. The correlation coefficient of 0.999 for the two detection systems is acceptable. In this research 77 edible oils were analyzed. The mean average value of 38 corn germ oils was 169 µg/kg, the maximum value amounted up to 921 µg/kg.

4.
J Agric Food Chem ; 48(9): 3979-84, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10995300

RESUMO

Within the European Union the determination of chaptalization of wine involves the comparison of the D/H ratios of ethanol with the ratios of authentic wine samples that are similar to the suspect wine in terms of geographical origin, grape variety, and vintage. In the frame of a databank project comparison, wines are produced under official control on a small scale. To clarify the influence of the different production conditions between commercial wines and these databank wines, wines that were produced under varying conditions were investigated by the (2)H NMR method. None of the parameters under investigation, such as yeast strain, fermentation temperature, or wine fining, showed a significant influence on the (D/H)(I) ratio of wine ethanol, which is the most indicative parameter for the determination of the addition of extraneous sugar to wine. For the (D/H)(II) ratio, different values were found for different yeast strains used for fermentation and a slight decrease was observed with increasing fermentation temperature. At increasing points of fermentation yield an increase of the D/H ratios was found in the present alcohol. The total increase of the (D/H)(I) ratio throughout the fermentation was approximately 1 ppm, so that with a fermentation yield of more than 50% no statistical difference could be observed.


Assuntos
Etanol/química , Vinho/análise , Metabolismo dos Carboidratos , Carboidratos/química , Etanol/metabolismo , Fermentação , Espectroscopia de Ressonância Magnética , Saccharomyces cerevisiae/metabolismo
5.
J AOAC Int ; 82(6): 1375-88, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10589492

RESUMO

An interlaboratory study of a gas chromatographic (GC) method for the determination of volatile congeners in spirit drinks was conducted; 31 laboratories from 8 countries took part in the study. The method uses GC with flame ionization detection and incorporates several quality control measures which permit the choice of chromatographic system and conditions to be selected by the user. Spirit drink samples were prepared and sent to participants as 10 blind duplicate or split-level test materials for the determination of 1,1-diethoxyethane (acetal), 2-methylbutan-1-ol (active amyl alcohol), 3-methylbutan-1-ol (isoamyl alcohol), methanol (methyl alcohol), ethyl ethanoate (ethyl acetate), butan-1-ol (n-butanol), butan-2-ol (sec-butanol), 2-methylpropan-1-ol (isobutyl alcohol), propan-1-ol (n-propanol), and ethanal (acetaldehyde). The precision of the method for 9 of the 10 analytes was well within the range predicted by the Horwitz equation. The precision of the most volatile analyte, ethanal, was just above statistically predicted levels. This method is recommended for official regulatory purposes.


Assuntos
Bebidas Alcoólicas/análise , Cromatografia Gasosa/métodos , 1-Propanol/análise , Acetaldeído/análise , Acetais/análise , Acetatos/análise , Butanóis/análise , Metanol/análise , Pentanóis/análise , Controle de Qualidade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Volatilização
6.
Biomed Environ Mass Spectrom ; 16(1-12): 161-5, 1988 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3242665

RESUMO

An analytical procedure for the isomer-specific quantification of polychlorinated dibenzo-p-dioxins and dibenzofurans in samples of human and animal origin is described. It consists of a large-scale clean-up including various kinds of column chromatography and high-resolution gas chromatographic/mass spectrometric quantification referring to internal 13C-labelled standards. By additional application of gel-permeation chromatography and the use of a retention gap, detection limits in the low ppq range (10(-15) were achieved.


Assuntos
Dioxinas/análise , Gorduras/análise , Contaminação de Alimentos/análise , Dibenzodioxinas Policloradas/análise , Animais , Carga Corporal (Radioterapia) , Gorduras na Dieta/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Isomerismo , Leite Humano/análise , Suínos
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