Aflatoxin B₁ (AFB₁) is a highly teratogenic and carcinogenic secondary metabolite produced by Aspergillus. It is commonly detected in agricultural products such as cereals, peanuts, corn, and feed. Grains have a complex composition. These complex components severely interfere with the effective extraction and separation of AFB₁, and also cause problems such as matrix interference and instrument damage, thus posing a great challenge in the accurate analysis of AFB₁. In this study, an aptamer affinity column for AFB₁ analysis (AFB₁-AAC) was prepared for the enrichment and purification of AFB₁ from grain samples. AFB₁-AAC with an AFB₁-specific aptamer as the recognition element exhibited high affinity and specificity for AFB₁. Grain samples were enriched and purified by AFB₁-AAC, and subsequently analyzed by high performance liquid chromatography with post-column photochemical derivatization-fluorescence detection (HPLC-PCD-FLD). The average recoveries of AFB₁ ranged from 88.7% to 99.1%, with relative standard deviations (RSDs) of 1.4–5.6% (n = 3) at the spiked levels of 5.0–20.0 μg kg⁻¹. The limit of detection (LOD) for AFB₁ (0.02 μg kg⁻¹) was much below the maximum residue limits (MRLs) for AFB₁. This novel method can be applied to the determination of AFB₁ residues in peanut, corn, and rice.

A new protocol for the separation and preconcentration of Cd(II) and Pb(II) in some food and water samples was developed using thiol-rich polyhedral oligomeric silsesquioxane-modified magnetic nanoparticles (Fe₃O₄@SiO₂/POSS-SH). The as-prepared magnetic adsorbent was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetoscopy. Cd(II) and Pb(II) were measured by ICP-OES after elution with 1 mL 1.0 mol L⁻¹ HNO₃. The influences of the analytical parameters including pH, eluent, sample volume, contact time and co-existing ions have been investigated in detail. The limits of detection were found to be 0.08 and 0.12 μg L⁻¹ for Cd and Pb, respectively, with an enrichment factor of 100. The proposed method was validated by two certified reference materials and applied successfully for the determination of Cd(II) and Pb(II) in rice, mushroom, pork, apple juice, bottled water and tap water with satisfied recoveries.

5-n-Alkylresorcinols (ARs) are abundant in wheat bran and potentially antioxidative, although the neuroprotective mechanism is not fully understood. The neuroprotective effect of wheat bran ARs on H₂O₂-induced neuronal cells and the relationship between neuroprotection and the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant-response element (ARE) pathway were investigated in this study. Seven homologs were identified in the purified ARs by high-performance liquid chromatography-tandem mass spectrometry. Pretreatment with 80 μg mL⁻¹ ARs alleviated 23% HT22 cell death and the up-regulation of intracellular reactive oxygen species level and malondialdehyde under H₂O₂ stimulation. The neuroprotection effect was proved by the increase in the Nrf2 nuclear location and up-regulation of mRNA and protein expressions of heme oxygenase-1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase catalytic subunit, and glutamate-cysteine ligase modifier subunit l. Wheat bran ARs displayed a neuroprotective function, possibly by promoting the endogenous antioxidant defense system. ARs may be regarded as a functional food ingredient for preventing neurodegenerative diseases in the future.