Bionic phase-transitioned α-lactalbumin coating for efficient separation of structurally similar environmental endocrine disruptors by open tubular capillary electrochromatography.

Environmental endocrine disruptors with estrogenic effects pose a significant threat to human health. However, many of these disruptors are homologues or isomers with similar structures, making them difficult to separate. Therefore, it is crucial to develop simple, rapid, and effective methods for their separation and detection. In this study, we developed a phase transition α-lactalbumin nanofilm (PTLA) using a fast phase transition preparation method. The nanofilm can stably adhere to various substrate surfaces and exhibits excellent stability under extreme conditions such as high-tack tape peeling, acid-alkali exposure, organic solvents, and high-pressure resistance. Its large specific surface area and abundant chemical groups enhance interactions with analytes. As a result, the PTLA-enhanced open tubular capillary electrochromatography (OT-CEC) achieved baseline separation of bisphenol homologs in 11 min and nitrophenol isomers in 7 min. Additionally, the PTLA-coated capillary demonstrated remarkable reusability, performing over 200 cycles with consistent peak shape and resolution. The relative standard deviations (RSDs) for intra-day, inter-day, and column-to-column repeatability were within 6.2%. Thus, PTLA coatings represent a significant advancement in separation science.