Electrospun nanofiber membranes for rapid on-site visual screening of eugenol residues in aquaculture, transportation, and holding water of aquatic products

Eugenol, a class of anesthetic agents widely used in fisheries transportation, poses potential risks to human health due to its residues in aquatic products. Therefore, developing a rapid, convenient, and sensitive method for rapid screening of eugenol residues is essential for on-site monitoring. In this study, a portable electrospun polylactic acid nanofiber membrane loaded with 4-nitrobenzenediazonium tetrafluoroborate (4-NBDT/PLA ENM) was developed for rapid on-site screening of eugenol and isoeugenol. Due to their structural similarity and natural coexistence in commercial eugenol preparations, the membrane responds collectively to these compounds rather than distinguishing them individually. The membrane exhibited good selectivity and anti-interference capability with an optimal reaction time of 15 min. The visual detection limit was 1.5 mg/L, while the instrumental limit of detection (LOD) and limit of quantification (LOQ) were 0.35 mg/L and 1.05 mg/L, respectively. The difference between visual and instrumental LOD is attributed to the lower sensitivity of visual observation compared with instrumental analysis, indicating that the ENM is suitable for rapid screening of relatively high-concentration samples during on-site monitoring. The membrane retained its detection capability for at least two months at 4 °C and was successfully applied to real water samples from aquaculture, transportation, and holding tanks, demonstrating its potential as a first-level screening tool for identifying potential misuse of eugenol.