Seo Miyeong, Kim Byungjoo, Baek Song-Yee
Division of Metrology for Quality of Life, Korea Research Institute of Standards and Science, Yuseong-gu, Daejeon, 305-340, Korea.
Anal Bioanal Chem. 2015 Jul;407(18):5433-42. doi: 10.1007/s00216-015-8705-3. Epub 2015 Apr 30.
Patulin, a mycotoxin produced by several molds in fruits, has been frequently detected in apple products. Therefore, regulatory bodies have established recommended maximum permitted patulin concentrations for each type of apple product. Although several analytical methods have been adopted to determine patulin in food, quality control of patulin analysis is not easy, as reliable certified reference materials (CRMs) are not available. In this study, as a part of a project for developing CRMs for patulin analysis, we developed isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC/MS/MS) as a higher-order reference method for the accurate value-assignment of CRMs. (13)C7-patulin was used as internal standard. Samples were extracted with ethyl acetate to improve recovery. For further sample cleanup with solid-phase extraction (SPE), the HLB SPE cartridge was chosen after comparing with several other types of SPE cartridges. High-performance liquid chromatography was performed on a multimode column for proper retention and separation of highly polar and water-soluble patulin from sample interferences. Sample extracts were analyzed by LC/MS/MS with electrospray ionization in negative ion mode with selected reaction monitoring of patulin and (13)C7-patulin at m/z 153→m/z 109 and m/z 160→m/z 115, respectively. The validity of the method was tested by measuring gravimetrically fortified samples of various apple products. In addition, the repeatability and the reproducibility of the method were tested to evaluate the performance of the method. The method was shown to provide accurate measurements in the 3-40 μg/kg range with a relative expanded uncertainty of around 1%.
展青霉素是由水果中的几种霉菌产生的一种霉菌毒素，在苹果制品中经常被检测到。因此，监管机构已为每种苹果制品制定了推荐的展青霉素最大允许浓度。尽管已采用多种分析方法来测定食品中的展青霉素，但由于没有可靠的有证标准物质（CRM），展青霉素分析的质量控制并不容易。在本研究中，作为展青霉素分析CRM开发项目的一部分，我们开发了同位素稀释液相色谱-串联质谱法（ID-LC/MS/MS）作为一种高阶参考方法，用于CRM的准确赋值。采用（13）C7-展青霉素作为内标。样品用乙酸乙酯萃取以提高回收率。为了通过固相萃取（SPE）进一步净化样品，在与其他几种类型的SPE柱进行比较后，选择了HLB SPE柱。在多模式柱上进行高效液相色谱分析，以便从样品干扰物中适当保留和分离高极性和水溶性的展青霉素。样品提取物通过LC/MS/MS进行分析，采用电喷雾电离负离子模式，分别对展青霉素和（13）C7-展青霉素进行m/z 153→m/z 109和m/z 160→m/z 115的选择反应监测。通过对各种苹果制品的重量法加标样品进行测量来测试该方法的有效性。此外，还测试了该方法的重复性和再现性，以评估该方法的性能。结果表明，该方法在3-40μg/kg范围内能提供准确的测量结果，相对扩展不确定度约为1%。
