Ethephon, a widely used growth regulator in fruits and vegetables, requires careful monitoring because of its toxicity. However, as far as we know, only two works are found in the literature regarding surface-enhanced Raman scattering (SERS) ethephon detection. Indeed, obtaining the SERS signal revealed to be challenging. Therefore, we have evaluated the SERS signal of ethephon using theoretical (as density functional theory and charge-assisted fragment interaction) and experimental approaches, addressing this limited literature knowledge. Theoretical Raman spectra with Ag or Au atoms at reactive sites exhibited enhanced ethephon SERS signal via AgCl bonding, consistent with the experimental data. Multiple experimental procedures were employed to obtain the SERS signal, including pH variations, salt addition, excitation laser lines, time dependency, and different SERS substrates (Ag colloid and Ag island films). Salt addition (NaCl) improved SERS signal, correlating with Ag colloid aggregation. Analysis in Ag colloid showed the pH 7.0 as optimal for ethephon detection, using freshly prepared Ag colloid + ethephon dispersion with ethephon powder being directly dissolved into Ag colloid. Only the AgCl band intensity improved with time. Ag colloid (wet medium — 633 nm laser line) outperformed Ag island films (dry medium — 785 nm laser line).

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用于乙烯利检测的表面增强拉曼散射信号的挑战：理论和实验方法

乙烯利是水果和蔬菜中广泛使用的生长调节剂，由于其毒性，需要仔细监测。然而，据我们所知，关于表面增强拉曼散射（SERS）乙烯利检测的文献中只有两篇作品。事实上，获得 SERS 信号具有挑战性。因此，我们利用理论（如密度泛函理论和电荷辅助片段相互作用）和实验方法评估了乙烯利的 SERS 信号，解决了有限的文献知识。反应位点上有 Ag 或 Au 原子的理论拉曼光谱通过 Ag - Cl 键合表现出增强的乙烯利 SERS 信号，与实验数据一致。采用多种实验程序来获得 SERS 信号，包括 pH 变化、盐添加、激发激光线、时间依赖性和不同的 SERS 基底（银胶体和银岛膜）。添加盐 (NaCl) 改善了 SERS 信号，与 Ag 胶体聚集相关。银胶体分析显示，使用新鲜制备的银胶体+乙烯利分散液，将乙烯利粉末直接溶解在银胶体中，pH 7.0 是乙烯利检测的最佳值。只有AgCl带强度随着时间的推移而提高。银胶体（湿介质 — 633 nm 激光线）优于银岛膜（干介质 — 785 nm 激光线）。