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Matthias Koch - One of the best experts on this subject based on the ideXlab platform.
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Novel Solid-Phase Extraction for Epimer-Specific Quantitation of Ergot Alkaloids in Rye Flour and Wheat Germ Oil
Journal of agricultural and food chemistry, 2013Co-Authors: Robert Köppen, Tatjana Rasenko, Stefan Merkel, Bettina Mönch, Matthias KochAbstract:Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na+-SCX) was developed to quantitate 12 priority ergot alkaloids in Rye Flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80–120% (Rye Flour) and 71–96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 μg kg–1 per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 Rye Flours (max 178 ± 5...
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Novel Solid-Phase Extraction for Epimer-Specific Quantitation of Ergot Alkaloids in Rye Flour and Wheat Germ Oil
Journal of agricultural and food chemistry, 2013Co-Authors: Robert Köppen, Tatjana Rasenko, Stefan Merkel, Bettina Mönch, Matthias KochAbstract:Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na(+)-SCX) was developed to quantitate 12 priority ergot alkaloids in Rye Flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80-120% (Rye Flour) and 71-96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 μg kg(-1) per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 Rye Flours (max 178 ± 5 μg kg(-1)) and, reported for the first time, 7 wheat germ oils (max 56.8 ± 2.7 μg kg(-1)) expressed as the sum of 12 ergot alkaloids.
R Merget - One of the best experts on this subject based on the ideXlab platform.
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Baker’s Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone
Advances in experimental medicine and biology, 2018Co-Authors: V. Van Kampen, R Merget, T Bruning, Ingrid Sander, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
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baker s asthma is the ratio of Rye Flour specific ige to total ige more suitable to predict the outcome of challenge test than specific ige alone
Advances in Experimental Medicine and Biology, 2018Co-Authors: V. Van Kampen, I Sander, R Merget, T Bruning, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
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Component-resolved diagnosis of baker's allergy based on specific IgE to recombinant wheat Flour proteins∗
The Journal of allergy and clinical immunology, 2015Co-Authors: Ingrid Sander, R Merget, Santiago Quirce, Hans-peter Rihs, Gert Doekes, Esmeralda Krop, P. Rozynek, Vera Van Kampen, Ursula Meurer, Thomas BrüningAbstract:Background Sensitization to wheat Flour plays an important role in the development and diagnosis of baker's asthma. Objectives We evaluated wheat allergen components as sensitizers for bakers with work-related complaints, with consideration of cross-reactivity to grass pollen. Methods Nineteen recombinant wheat Flour proteins and 2 cross-reactive carbohydrate determinants were tested by using CAP-FEIA in sera of 101 bakers with wheat Flour allergy (40 German, 37 Dutch, and 24 Spanish) and 29 pollen-sensitized control subjects with wheat-specific IgE but without occupational exposure. IgE binding to the single components was inhibited with wheat Flour, Rye Flour, and grass pollen. The diagnostic efficiencies of IgE tests with single allergens and combinations were evaluated by assessing their ability to discriminate between patients with baker's allergy and control subjects based on receiver operating characteristic analyses. Results Eighty percent of bakers had specific IgE levels of 0.35 kU A /L or greater and 91% had specific IgE levels of 0.1 kU A /L or greater to at least one of the 21 allergens. The highest frequencies of IgE binding were found for thiol reductase (Tri a 27) and the wheat dimeric α-amylase inhibitor 0.19 (Tri a 28). Cross-reactivity to grass pollen was proved for 9 components, and cross-reactivity to Rye Flour was proved for 18 components. A combination of IgE tests to 5 components, Tri a 27, Tri a 28, tetrameric α-amylase inhibitor CM2 (Tri a 29.02), serine protease inhibitor–like allergen (Tri a 39), and 1-cys-peroxiredoxin (Tri a 32), produced the maximal area under the curve (AUC = 0.84) in receiver operating characteristic analyses, but this was still lower than the AUC for wheat- or Rye Flour–specific IgE (AUC = 0.89 or 0.88, respectively). Conclusions Component-resolved diagnostics help to distinguish between sensitization caused by occupational Flour exposure and wheat seropositivity based on cross-reactivity to grass pollen. For routine diagnosis of baker's allergy, however, allergen-specific IgE tests with whole wheat and Rye Flour extracts remain mandatory because of superior diagnostic sensitivity.
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Comparison of wheat and Rye Flour solutions for skin prick testing: a multi-centre study (Stad 1).
Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, 2009Co-Authors: V. Van Kampen, Sylvia Rabstein, R Merget, Horst Christoph Broding, C Keller, A Overlack, Ingrid Sander, Thomas Bruening, H Muesken, Gerhard Schultze-werninghausAbstract:Summary Background Skin prick testing (SPT) is the basic method for diagnosing IgE-mediated allergies. However, skin reactivity is related to the quality of allergen extracts, which are often poorly defined for occupational allergens. Objective To compare wheat and Rye Flour SPT solutions from different producers. Materials and methods Standardized SPTs were performed in seven allergy centres with wheat and Rye Flour solutions from four producers in 125 symptomatic bakers. Optimal cut-off levels for weal sizes were assessed with the Youden Index. Comparisons between SPT results of different solutions were made with Flour-specific IgE (sIgE) as the gold standard. Sensitivities, specificities, positive and negative predictive values, and test efficiencies were calculated and compared with McNemar and χ2-tests. The influence of the choice of the gold standard (sIgE or challenge) test was examined for 95 subjects. Additionally, SPT solutions were analysed for protein and antigen content. Results The optimal cut-off level for all SPT solutions was a weal size of 1.5 mm. While differences between wheat and Rye Flours were small, differences between producers were important. Variability of sensitivities (0.31–0.96), negative predictive values (0.42–0.91), and test efficiencies (0.54–0.90) were higher than variations of specificities (0.74–1.00) and positive predictive values (0.88–1.00). Similar results were obtained when using challenge test results as the gold standard. Variability could be explained by the different antigen contents of the SPT solutions. Conclusion There is a wide variability of SPT solutions for wheat and Rye Flour from different producers, mainly with respect to sensitivities, negative predictive values, and test efficiencies. Improvement and standardization of SPT solutions used for the diagnosis of baker's asthma are highly recommended.
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prediction of challenge test results by Flour specific ige and skin prick test in symptomatic bakers
Allergy, 2008Co-Authors: V Van Kampen, Sylvia Rabstein, I Sander, R Merget, T Bruning, Horst Christoph Broding, C Keller, H Musken, A Overlack, G SchultzewerninghausAbstract:Background: Wheat and Rye Flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker’s asthma is based on inhalation challenge tests with Flours. Aims of the study: To evaluate the relevance of Flour-specific serum immunoglobulin E (IgE) and skin prick test (SPT) in the diagnosis of baker’s asthma and to define Flour-specific IgE concentrations and wheal sizes that allow a prediction of the outcome of challenge testing. Methods: Bronchial and nasal challenge tests with wheat (Rye) Flour were performed in 71 (95) symptomatic bakers. Determinations of Flour-specific IgE as well as SPTs were performed in all subjects. Analyses included the calculation of sensitivity, specificity, positive (PPV) and negative predictive values (NPV) at different IgE concentrations and different wheal sizes, and receiver-operating characteristics (ROC) plots with the challenge result as gold standard. Results: Thirty-seven bakers were positive in the challenge with wheat Flour, while 63 were positive with Rye Flour. Depending on the Flour-specific IgE concentrations (wheal size), PPV was 74–100% (74–100%) for wheat and 82–100% (91–100%) for Rye Flour, respectively. The minimal cut-off values with a PPV of 100% were 2.32 kU/l (5.0 mm) for wheat Flour and 9.64 kU/l (4.5 mm) for Rye Flour. The shapes of the ROC plots were similar for wheat and Rye Flour. Conclusion: High concentrations of Flour-specific IgE and clear SPT results in symptomatic bakers are good predictors for a positive challenge test. Challenge tests with Flours may be avoided in strongly sensitized bakers.
Monika Raulf - One of the best experts on this subject based on the ideXlab platform.
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Baker’s Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone
Advances in experimental medicine and biology, 2018Co-Authors: V. Van Kampen, R Merget, T Bruning, Ingrid Sander, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
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baker s asthma is the ratio of Rye Flour specific ige to total ige more suitable to predict the outcome of challenge test than specific ige alone
Advances in Experimental Medicine and Biology, 2018Co-Authors: V. Van Kampen, I Sander, R Merget, T Bruning, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
T Bruning - One of the best experts on this subject based on the ideXlab platform.
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Baker’s Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone
Advances in experimental medicine and biology, 2018Co-Authors: V. Van Kampen, R Merget, T Bruning, Ingrid Sander, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
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baker s asthma is the ratio of Rye Flour specific ige to total ige more suitable to predict the outcome of challenge test than specific ige alone
Advances in Experimental Medicine and Biology, 2018Co-Authors: V. Van Kampen, I Sander, R Merget, T Bruning, Monika RaulfAbstract:Usually the diagnosis of baker’s asthma is based on specific inhalation challenge with Flours. To a certain extent the concentration of specific IgE to Flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with Rye Flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of Rye Flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.
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prediction of challenge test results by Flour specific ige and skin prick test in symptomatic bakers
Allergy, 2008Co-Authors: V Van Kampen, Sylvia Rabstein, I Sander, R Merget, T Bruning, Horst Christoph Broding, C Keller, H Musken, A Overlack, G SchultzewerninghausAbstract:Background: Wheat and Rye Flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker’s asthma is based on inhalation challenge tests with Flours. Aims of the study: To evaluate the relevance of Flour-specific serum immunoglobulin E (IgE) and skin prick test (SPT) in the diagnosis of baker’s asthma and to define Flour-specific IgE concentrations and wheal sizes that allow a prediction of the outcome of challenge testing. Methods: Bronchial and nasal challenge tests with wheat (Rye) Flour were performed in 71 (95) symptomatic bakers. Determinations of Flour-specific IgE as well as SPTs were performed in all subjects. Analyses included the calculation of sensitivity, specificity, positive (PPV) and negative predictive values (NPV) at different IgE concentrations and different wheal sizes, and receiver-operating characteristics (ROC) plots with the challenge result as gold standard. Results: Thirty-seven bakers were positive in the challenge with wheat Flour, while 63 were positive with Rye Flour. Depending on the Flour-specific IgE concentrations (wheal size), PPV was 74–100% (74–100%) for wheat and 82–100% (91–100%) for Rye Flour, respectively. The minimal cut-off values with a PPV of 100% were 2.32 kU/l (5.0 mm) for wheat Flour and 9.64 kU/l (4.5 mm) for Rye Flour. The shapes of the ROC plots were similar for wheat and Rye Flour. Conclusion: High concentrations of Flour-specific IgE and clear SPT results in symptomatic bakers are good predictors for a positive challenge test. Challenge tests with Flours may be avoided in strongly sensitized bakers.
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comparison of wheat and Rye Flour skin prick test solutions for diagnosis of baker s asthma
Allergy, 2004Co-Authors: I Sander, R Merget, T Bruning, P Degens, N Goldscheid, M RaulfheimsothAbstract:Background: Skin prick tests (SPTs) play an important role in the diagnosis of baker's asthma and in the investigation of sensitization frequencies in field studies. It was the aim of our study to compare different SPT solutions for wheat and Rye Flour sensitization and to assess the validity of test results. Methods: Skin prick tests with wheat and Rye Flour were performed in parallel with extracts from different companies and compared with the results of bronchial challenge tests with both Flours (69 Rye Flour and 51 wheat Flour challenge tests). Additionally, specific immunoglobulin E (sIgE) to wheat and Rye Flour were tested. SPT solutions were analysed for protein content and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results: Skin prick test solutions for diagnosis of wheat and Rye Flour sensitization from three companies differed in protein concentrations and composition with the consequence of widely differing SPT results. Sensitivity of SPTs in comparison with allergen-specific bronchial challenge as a gold standard was between 40 and 67%, specificity was between 86 and 100%, the positive predictive value (PPV) ranged from 81 to 100% and the negative predictive value (NPV) from 44 to 70%. These numbers were only marginally affected by using a combination of challenge test result and sIgE value as a more specific gold standard. Conclusion: Improvement and standardization of SPT extracts for wheat and Rye Flour is highly recommended.
Robert Köppen - One of the best experts on this subject based on the ideXlab platform.
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Novel Solid-Phase Extraction for Epimer-Specific Quantitation of Ergot Alkaloids in Rye Flour and Wheat Germ Oil
Journal of agricultural and food chemistry, 2013Co-Authors: Robert Köppen, Tatjana Rasenko, Stefan Merkel, Bettina Mönch, Matthias KochAbstract:Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na+-SCX) was developed to quantitate 12 priority ergot alkaloids in Rye Flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80–120% (Rye Flour) and 71–96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 μg kg–1 per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 Rye Flours (max 178 ± 5...
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Novel Solid-Phase Extraction for Epimer-Specific Quantitation of Ergot Alkaloids in Rye Flour and Wheat Germ Oil
Journal of agricultural and food chemistry, 2013Co-Authors: Robert Köppen, Tatjana Rasenko, Stefan Merkel, Bettina Mönch, Matthias KochAbstract:Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na(+)-SCX) was developed to quantitate 12 priority ergot alkaloids in Rye Flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80-120% (Rye Flour) and 71-96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 μg kg(-1) per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 Rye Flours (max 178 ± 5 μg kg(-1)) and, reported for the first time, 7 wheat germ oils (max 56.8 ± 2.7 μg kg(-1)) expressed as the sum of 12 ergot alkaloids.
