Semiconductor heterojunction with functional integration can be used as an excellent matrix for the ultrasensitive detection of bisphenol A (BPA) with low molecular affinity. Here, a simple, low-cost and sensitive surface-enhanced Raman scattering (SERS) strategy using g-C₃N₄/TiO₂ heterojunction as substrate was presented for detection of BPA residues in foods. The g-C₃N₄/TiO₂ achieved specific chemisorption for target analyte by the formation of intermolecular H-bond between g-C₃N₄ and BPA. And, a high-efficiency carrier separation in TiO₂ induced by heterostructure could be achieved for charge transfer between the substrate and molecule by a “donor-bridge-acceptor” charge-transfer mode. Due to the synergistic/collaborative contributions of two monomers in heterojunction, the SERS enhancement factor was as high as 3.77 × 10⁷. The detection limit of BPA residues in foods (milk, juice and drinking water) was as low as 10⁻⁹ mol·L⁻¹, far below the EU standard. The developed substrate also exhibited excellent stability and anti-interference capability.

中文翻译：

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一种用于双酚 a 残留超灵敏检测的新型 g-C3N4/TiO2 异质结


具有功能集成的半导体异质结可用作超灵敏检测低分子亲和力双酚 A （BPA） 的优良基质。在这里，提出了一种使用 g-C₃N₄/TiO₂ 异质结作为基材的简单、低成本且灵敏的表面增强拉曼散射 （SERS） 策略，用于检测食品中 BPA 残留。g-C₃N₄/TiO₂ 通过在 g-C₃N₄ 和 BPA 之间形成分子间 H 键，实现了对目标分析物的特异性化学吸附。并且，通过“供体-桥-受体”电荷转移模式，可以在异质结构诱导的 TiO₂ 中实现高效的载流子分离，以实现衬底和分子之间的电荷转移。由于两种单体在异质结中的协同/协同作用，SERS 增强因子高达 3.77 × 10⁷。食品（牛奶、果汁和饮用水）中BPA残留的检出限低至10⁻⁹ mol·L⁻¹，远低于欧盟标准。开发的基板还表现出优异的稳定性和抗干扰能力。