Lateral flow immunoassay (LFIA) is a promising tool for rapid detection in the field of agricultural product analysis due to its advantages of cost-effectiveness and operational simplicity. In this work, Eu metal–organic frameworks (MOFs) were introduced to LFIA as a rapid detection method characterized by high stability and low interference. Key research objectives included strong fluorescence, ease of labeling, and the utilization of fluorescent probes. Eu-MOFs were synthesized in one step via the hydrothermal method, exhibiting a fluorescence lifetime of 163 μs and spherical particles with diameters ranging from 250 to 400 nm. These conditions fulfill the characteristics and requirements of LFIA. Eu-MOFs exploit the porous nature of MOFs to mitigate the drawbacks associated with complex crosslinking agents. This enables antibody proteins to be cross-linked merely upon contact, thereby simplifying the detection process. A time-resolved LFIA method was developed utilizing Eu-MOFs for the detection of aflatoxin B1 (AFB1) in corn, achieving a limit of detection (LOD, IC10) of 0.149 ng/mL. The accuracy and reliability of the Eu-MOFs-LFIA method were validated through comparisons with spiked concentrations during spiking and blind sample analyses, with verification conducted using ultra-high-performance liquid chromatography mass spectrometry (UPLC-MS). Furthermore, testing of real samples demonstrated that the Eu-MOFs-LFIA method can effectively facilitate rapid detection of AFB1 in corn.

Lotus sprouts are a widely consumed aquatic vegetable, yet their quality remains poorly characterized. This study integrated physicochemical analysis, volatile flavor profiling, and metabolomics to evaluate quality differences among three lotus sprout cultivars, as well as different parts and grades. The apical portions had significantly higher contents of protein, total phenolics, and γ-aminobutyric acid than the stem portions. A total of 46 volatile compounds were identified by headspace solid-phase micro-extraction combined with gas chromatography–mass spectrophotometry (HS-SPME-GC-MS), and the abundance of 2,4-di-tert-butylphenol and 1-octen-3-ol was further confirmed using standards. Untargeted metabolomics identified 335 compounds, with sugars, polyphenols, and amino acids being the most abundant categories. Differentially accumulated metabolites between parts and cultivars were significantly enriched in glutathione metabolism, flavonoid biosynthesis, and amino acid metabolism. Notably, the two Baiyuzan cultivars generally accumulated higher levels of beneficial metabolites than Wuzhi No. 2, whereas the stem portion of the higher-grade Wuzhi No. 2 showed lower accumulation of sucrose and paprazine. Quantitative analysis of eight alkaloids using external standard calibration curves indicated that nuciferine was the most abundant alkaloid (13.3 to 31.1 μg/g). Collectively, this study provides a foundational framework for evaluating the metabolite profiles and application potential of lotus sprouts.