The surface-enhanced Raman scattering (SERS) substrates enable a highly sensitive detection of furfural in the transformer oil. However, detection substrates with long-term stability are still extremely challenging. In this work, we anchored the thiol-containing coupling agents 2, 5-dimercapto-1, 3, 4-thiadiazole (DMTD) and 1, 4-benzenedithiol (BDT) on the surface of bubble copper (B-Cu) and flower-like silver nanoparticles (F-Ag), respectively. The three-dimensional SERS detection substrates with long-term stability by using a combination of chemical reduction and self-assembly methods were constructed. The substrate has a minimum detection limit of 10⁻⁹ M for rhodamine B in oil with an enhancement factor of up to 2.23 × 10⁷. Importantly, the three-crystal B-Cu@F-Ag₁@Au₅ substrate was used for the detection of furfural in the transformer oil with a detection limit of 2 mg/L and a relative standard deviation value of 2.46%. After 60 days of a simulated operation, the detection signal of furfural in the transformer oil samples at 75°C and still reached the initial value of 77.53%, indicating that the substrate has a good long-term stability. This triple frame structured SERS detection platform shows great potential in tracking furfural in the aging transformer oil mixing systems.

中文翻译：

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具有长期稳定性的功能化 B-Cu@F-Ag@Au 三金属纳米材料可快速、高灵敏度地原位 SERS 检测变压器油中的糠醛

表面增强拉曼散射 (SERS) 基板能够高度灵敏地检测变压器油中的糠醛。然而，具有长期稳定性的检测底物仍然极具挑战性。在这项工作中，我们将含硫醇的偶联剂 2, 5-dimercapto-1, 3, 4-thiadiazole (DMTD) 和 1, 4-benzenedithiol (BDT) 锚定在泡铜 (B-Cu) 和花的表面-分别像银纳米粒子 (F-Ag)。采用化学还原和自组装相结合的方法构建了具有长期稳定性的三维SERS检测基板。该底物对油中的罗丹明 B 的最低检测限为 10 ^-9  M，增强因子高达 2.23 × 10 ⁷。重要的是，三晶 B-Cu@F-Ag ₁@Au ₅底物用于变压器油中糠醛的检测，检出限为2 mg/L，相对标准偏差值为2.46%。模拟运行60天后，75℃变压器油样品中糠醛检测信号仍达到初始值77.53%，表明该底物具有良好的长期稳定性。这种三框架结构的 SERS 检测平台显示出跟踪老化变压器油混合系统中糠醛的巨大潜力。