AbstractA novel adsorbent is described for magnetic solid-phase extraction (MSPE) of the aflatoxins AFB1 and AFB2 (AFBs). Magnetic agarose microspheres (MAMs) were functionalized with an aptamer to bind the AFBs which then were quantified by HPLC and on-line post-column photochemical derivatization with fluorescence detection. Streptavidin-conjugated MAMs were synthesized first by a highly reproducible strategy. They possess strong magnetism and high surface area. The MAMs were characterized by transmission electron microscopy, scanning electron microscopy, optical microscopy, laser diffraction particle size analyzer, Fourier transform infrared spectrometry, vibrating sample magnetometry and laser scanning confocal microscopy. Then, the AFB-aptamers were immobilized on MAMs through biotin–streptavidin interaction. Finally, the MSPE is performed by suspending the aptamer-modified MAMs in the sample. They are then collected by an external magnetic field and the AFBs are eluted with methanol/buffer (20:80). Several parameters affecting the coupling, capturing and eluting efficiency were optimized. Under the optimized conditions, the method is fast, has good linearity, high selectivity, and sensitivity. The LODs are 25 pg·mL−1 for AFB1 and 10 pg·mL−1 for AFB2. The binding capacity is 350 ± 8 ng·g−1 for AFB1 and 384 ± 8 ng·g−1 for AFB2, and the precision of the assay is <8%. The method was successfully applied to the analysis of AFBs in spiked maize samples. Graphical abstractSchematic of novel aptamer functionalized magnetic agarose microspheres (Apt-MAM) as magnetic adsorbents for simultaneous and specific affinity capture of aflatoxins B1 and B2 (AFBs).

中文翻译：

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在 HPLC 测定之前，通过适体功能化的磁性琼脂糖微球亲和捕获黄曲霉毒素 B1 和 B2

摘要描述了一种用于黄曲霉毒素 AFB1 和 AFB2 (AFB) 的磁性固相萃取 (MSPE) 的新型吸附剂。磁性琼脂糖微球 (MAM) 用适体功能化以结合 AFB，然后通过 HPLC 和带有荧光检测的在线柱后光化学衍生化进行定量。首先通过高度可重复的策略合成链霉亲和素偶联的 MAM。它们具有强磁性和高表面积。通过透射电子显微镜、扫描电子显微镜、光学显微镜、激光衍射粒度分析仪、傅里叶变换红外光谱、振动样品磁强计和激光扫描共聚焦显微镜对 MAM 进行了表征。然后，通过生物素-链霉亲和素相互作用将 AFB 适配体固定在 MAM 上。最后，MSPE 是通过在样品中悬浮适体修饰的 MAM 来进行的。然后通过外部磁场收集它们，并用甲醇/缓冲液 (20:80) 洗脱 AFB。优化了影响偶联、捕获和洗脱效率的几个参数。在优化的条件下，该方法速度快、线性好、选择性和灵敏度高。AFB1 的 LOD 为 25 pg·mL-1，AFB2 的 LOD 为 10 pg·mL-1。AFB1的结合能力为350±8 ng·g-1，AFB2的结合能力为384±8 ng·g-1，检测精度<8%。该方法已成功应用于加标玉米样品中 AFB 的分析。图解摘要新型适体功能化磁性琼脂糖微球 (Apt-MAM) 作为磁性吸附剂用于同时和特异性亲和捕获黄曲霉毒素 B1 和 B2 (AFB) 的示意图。