Krska Rudolf, Berthiller Franz, Schuhmacher Rainer, Nielsen Kristian F, Crews Colin
University of Natural Resources and Applied Life Sciences Vienna, Christian Doppler Laboratory for Mycotoxin Research, Department for Agrobiotechnology (IFA-Tulln), Konrad Lorenz Strasse 20, 3430 Tulln, Austria.
J AOAC Int. 2008 Nov-Dec;91(6):1363-71.
Results obtained from a purity study on standards of the 6 major ergot alkaloids ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, and ergocornine and their corresponding epimers are discussed. The 6 ergot alkaloids studied have been defined by the European Food Safety Authority as those that are the most common and physiologically active. The purity of the standards was investigated by means of liquid chromatography with diode array detection, electrospray ionization, and time-of-flight mass spectrometry (LC-DAD-ESI-TOF-MS). All of the standards assessed showed purity levels considerably above 98% apart from ergocristinine (94%), ergosine (96%), and ergosinine (95%). Also discussed is the optimization of extraction conditions presented in a recently published method for the quantitation of ergot alkaloids in food samples using solid-phase extraction with primary secondary amine (PSA) before LC/MS/MS. Based on the results obtained from these optimization studies, a mixture of acetonitrile with ammonium carbonate buffer was used as extraction solvent, as recoveries for all analyzed ergot alkaloids were significantly higher than those with the other solvents. Different sample-solvent ratios and extraction times showed just minor influences in extraction efficacy. Finally, the stability of the ergot alkaloids in both raw cereals and cereal-based processed food extracts was studied. According to these studies, extracts should be prepared and analyzed the same day or stored below ambient temperatures. Barley and rye extracts, which were stored at 4 and 15 degrees C after PSA cleanup, proved to be stable overnight. However, storage over a period of 14 days at 4 degrees C resulted in significant epimerization, which was most pronounced in rye and particularly for ergocornine, ergocryptine, and ergocristine.
讨论了对6种主要麦角生物碱麦角新碱、麦角胺、麦角异碱、麦角克碱、麦角隐亭和麦角柯宁及其相应差向异构体标准品进行纯度研究所得的结果。欧洲食品安全局已将所研究的这6种麦角生物碱定义为最常见且具有生理活性的生物碱。通过二极管阵列检测液相色谱法、电喷雾电离和飞行时间质谱法（LC-DAD-ESI-TOF-MS）对标准品的纯度进行了研究。除麦角克碱（94%）、麦角异碱（96%）和麦角异新碱（95%）外，所有评估的标准品纯度水平均大大高于98%。还讨论了最近发表的一种方法中提取条件的优化，该方法用于在LC/MS/MS之前使用伯仲胺（PSA）固相萃取对食品样品中的麦角生物碱进行定量。基于这些优化研究的结果，使用乙腈与碳酸铵缓冲液的混合物作为提取溶剂，因为所有分析的麦角生物碱的回收率均显著高于使用其他溶剂时的回收率。不同的样品-溶剂比例和提取时间对提取效率的影响较小。最后，研究了麦角生物碱在原粮和谷物加工食品提取物中的稳定性。根据这些研究，提取物应在同一天制备和分析，或储存在环境温度以下。经PSA净化后在4℃和15℃储存的大麦和黑麦提取物在过夜后证明是稳定的。然而，在4℃下储存14天会导致显著的差向异构化，这在黑麦中最为明显，尤其是对于麦角柯宁、麦角隐亭和麦角克碱。
