Animal Health and Environment "BIOR", Institute of Food Safety, Lejupes iela 3, Riga, LV 1076, Latvia.
Animal Health and Environment "BIOR", Institute of Food Safety, Lejupes iela 3, Riga, LV 1076, Latvia; Faculty of Chemistry, University of Latvia, Jelgavas iela 1, Riga, LV 1004, Latvia.
J Chromatogr A. 2022 Aug 2;1676:463269. doi: 10.1016/j.chroma.2022.463269. Epub 2022 Jun 21.
A method for the determination of pyrrolizidine alkaloids in tea, honey, herbal tinctures, and milk samples was developed by employing nano-LC-MS with high-resolution Orbitrap mass spectrometry. Quantitation was performed using the available analytical standards, and a MS target ion screening approach was developed using fragment ions that were specific for pyrrolizidine alkaloids under collision-induced dissociation. Proof of concept was delivered for the screening approach, proposing that the CHN fragment ion is a highly selective fragment ion for the detection of potential pyrrolizidine alkaloids. The elaborated quantitation was applied for the occurrence study of pyrrolizidine alkaloids in food products available on the Latvian market, including samples of tea (n = 15), honey (n = 40), herbal tinctures (n = 15), and milk (n = 10). The median LOQ over all analytes was 0.33 µg kg in honey, 3.6 µg kg in tea, 3.3 µg kg in herbal tinctures, and 0.32 µg kg in milk. The herbal tinctures samples and milk samples did not contain pyrrolizidine alkaloids above LOQ values. Analytes were detected in 33% of honey and 47% of tea samples. Most common were echimidine, intermedine, and enchinatine N-oxide. Pyrrolizidine alkaloids in tea samples were mainly N-oxides, with the highest total concentration being 215 µg kg among the samples, exceeding the maximum limit of 200 µg kg set by Commission Regulation (EU) 2020/2040. In honey samples, lycopsamine-type alkaloids were detected most frequently, with the highest total concentration equal to 74 µg kg. Advantages of the developed nano-LC-MS methods included increased sensitivity in comparison with conventional flow LC-MS, low solvent consumption typical with nano-LC and the novel use of a selective common target ion for detection and discovery of potential pyrrolizidine alkaloids using high resolution mass spectrometry.
建立了一种采用纳升液相色谱-高分辨轨道阱质谱联用技术测定茶叶、蜂蜜、草药酊剂和牛奶样品中吡咯里西啶生物碱的方法。采用已有的分析标准品进行定量，通过在碰撞诱导解离下对吡咯里西啶生物碱具有特异性的碎片离子，开发了一种 MS 目标离子筛选方法。该方法提出了 CHN 碎片离子是检测潜在吡咯里西啶生物碱的高度选择性碎片离子，为筛选方法提供了概念验证。该方法还用于研究拉脱维亚市场上食品中吡咯里西啶生物碱的发生情况，包括茶叶（n=15）、蜂蜜（n=40）、草药酊剂（n=15）和牛奶（n=10）样品。所有分析物的 LOQ 中位数在蜂蜜中为 0.33μg/kg，在茶中为 3.6μg/kg，在草药酊剂中为 3.3μg/kg，在牛奶中为 0.32μg/kg。在 LOQ 值以上，草药酊剂和牛奶样品中未检出吡咯里西啶生物碱。在 33%的蜂蜜和 47%的茶样品中检测到了分析物。最常见的是echimidine、intermedine 和 enchinatine N-oxide。茶样中的吡咯里西啶生物碱主要为 N-氧化物，其中样品中总浓度最高为 215μg/kg，超过委员会法规（EU）2020/2040 规定的 200μg/kg 限量。在蜂蜜样品中，最常检测到 lycopsamine 型生物碱，总浓度最高为 74μg/kg。与传统的流动相 LC-MS 相比，所开发的纳升 LC-MS 方法具有更高的灵敏度，与纳升 LC 典型的低溶剂消耗以及使用高分辨率质谱对潜在吡咯里西啶生物碱进行检测和发现的新型选择性通用目标离子相结合，具有独特的优势。
