Matrix effects are a great challenge for the quantitative analysis of complex food samples by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS). Stable isotope labeling (SIL) has been widely used as an effective strategy to eliminate matrix effects. Herein, a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click-reaction-based SIL method was proposed for a highly sensitive and selective determination of six synthetic steroid hormones in three different food samples (milk, yogurt, and eggs) by high-performance liquid chromatography (HPLC)-MS/MS. A pair of novel SIL agents, N-(2-azidyl ethyl) aniline (d₀-AEA) and d₅-N-(2-azidyl ethyl) aniline (d₅-AEA) were synthesized to label steroid hormones in the samples and standard solution, respectively. The reaction accomplishes in 30 min at 60 °C. The heavy labeled standards were used as internal standards (ISs), which experience the identical ionization processes with light labeled samples to minimize matrix effects. After derivatization, the ionization efficiencies of steroid hormones were greatly improved by 2–54-folds, and the matrix effects ranged from 88.6 to 99.8%. The established method achieved satisfactory detection limits (0.1–2.5 μg L^–1) and high recoveries (85–102%). These results demonstrated that the proposed method holds unique advantages for trace steroid hormones analysis in foodstuffs.

中文翻译：

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Click Isotope Mass Probe 用于高选择性测定食品样品中的痕量类固醇激素

基质效应是液相色谱-串联质谱分析 (LC-MS/MS) 对复杂食品样品进行定量分析的一大挑战。稳定同位素标记 (SIL) 已被广泛用作消除基质效应的有效策略。在此，提出了一种基于铜 (I) 催化的叠氮化物-炔烃环加成 (CuAAC) 的点击反应的 SIL 方法，用于高灵敏度和选择性地测定三种不同食品样品（牛奶、酸奶和鸡蛋）中的六种合成类固醇激素通过高效液相色谱 (HPLC)-MS/MS。一对新型SIL试剂，N- (2-叠氮基乙基)苯胺( d ₀ -AEA)和d ₅ -N- ( 2-叠氮基乙基)苯胺( d _{5 )}-AEA) 被合成以分别标记样品和标准溶液中的类固醇激素。反应在 60 °C 下在 30 分钟内完成。重标记标准被用作内标 (IS)，它与轻标记样品经历相同的电离过程，以最大限度地减少基质效应。衍生化后，类固醇激素的电离效率大大提高了2-54倍，基质效应在88.6-99.8%之间。建立的方法达到了令人满意的检测限 (0.1–2.5 μg L ^–1 ) 和高回收率 (85–102%)。这些结果表明，所提出的方法对于食品中的痕量类固醇激素分析具有独特的优势。