排序方式: 共有121条查询结果,搜索用时 31 毫秒
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R. D. Josephs R. Krska R. Schuhmacher M. Grasserbauer 《Fresenius' Journal of Analytical Chemistry》1999,363(1):130-131
The development of a rapid method for the determination of the Fusarium mycotoxin beauvericin (BEA) in corn and cereals is described. This method allows to prepare at least 5 times more samples
simultaneously with similar analytical performance characteristics as previously published analytical methods.
Received: 14 May 1998 / Revised: 9 July 1998 / Accepted: 14 July 1998 相似文献
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Ryan D. Cohen Josep Saurí Chelsea A. Huff Shane W. Krska Gary E. Martin 《Magnetic resonance in chemistry : MRC》2016,54(11):897-900
1,1‐ADEQUATE is a powerful and robust NMR experiment to establish carbon–carbon connectivities using modest sample quantities when cryogenic probe technology is available. Yet potential pitfalls of applying this method are not widely appreciated, such as weak or missing 1JCC correlations in strongly coupled 13C‐13C AB spin systems and unusually large multi‐bond (nJCC) correlations associated with particular functional groups. These large nJCC correlations observed in 1,1‐ADEQUATE spectra could be mistaken for 1JCC correlations. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Wolfgang Kandler Rainer Schuhmacher Susanne Roch Patricia Schubert-Ullrich Rudolf Krska 《Accreditation and quality assurance》2004,9(1-2):82-89
After 7 years of successful operation, the database of the proficiency testing (PT) scheme for water analysis organized by the Institute for Agrobiotechnology (IFA), Tulln contains nearly 4,000 data sets from over 300 interlaboratory comparison samples. About 70 analytical parameters (major ions, metals, trace ions, herbicides, volatile halogenated hydrocarbons, organochlorine pesticides and polycyclic aromatic hydrocarbons) were covered by the PT scheme. The data were evaluated using robust statistics in order to determine a set of coefficients of variation (CV) for each analytical parameter. Concentration and time dependence of the CV were checked. The CV were combined to obtain standard deviations for proficiency assessment (Z-score criteria). Furthermore, a viewer program was designed to facilitate monitoring of the analytical performance of participating laboratories. 相似文献
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Oliver Mann Elisabeth Pock Klaus Wruss Werner Wruss Rudolf Krska 《International journal of environmental analytical chemistry》2016,96(4):353-372
The present work describes a fully automated method based on online solid phase extraction–liquid chromatography–tandem mass spectrometry for the determination of different classes of pesticides, including acidic and polar pesticides and six thiamethoxam metabolites. Sample preconcentration was performed by extracting 4 mL of the sample with a single styrene-divinylbenzene polymer. Elution of the compounds was done within the high performance liquid chromatography gradient and tandem mass spectrometry determination was performed in the selected reaction monitoring mode, by recording 1–3 transitions per compound. The overall pretreatment and analysis time per sample was less than 15 min. Method validation was performed in drinking, ground and surface water. For nearly all compounds a recovery between 70% and 120% could be achieved. The limit of detection ranges from 1.2 to 18 ng/L in drinking water and 3.0 to 23 ng/L in ground and surface water. The correlation coefficients for a calibration range of 0.05–2 µg/L are between 0.9915 and 0.9999. The limit of quantification (LOQ) for all compounds lies below the required limit of 0.1 µg/L, to fulfil the Council Directive 98/83/EC. Most of the compounds easily reach an LOQ below 0.05 µg/L. 相似文献
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Methods for the determination of toxic pyrrolizidine alkaloids in plants and foods are described with emphasis on the important
aspects of sample extraction and clean-up and the now preferred determination by liquid chromatography–mass spectrometry.
The efficiencies of different extraction solvents and methods are described, as are the methods of reduction of N-oxides. Appropriate liquid chromatography–mass spectrometry conditions are tabulated. This concise review is intended to
guide analysts towards adopting a more unified and reliable approach to the analysis of these important toxins. 相似文献