The study of the interaction of the herbicide glyphosate with zinc oxide (ZnO) nanocrystals (NCs) was investigated under controlled pH conditions. These changes alter the various chemical groups’ vibrational frequencies of the glyphosate molecule according to the infrared spectra. Scanning electron microscopy (SEM), and atomic force microscopy (AFM) images suggest that the pH changes promote specific conformational changes due to the protonation of glyphosate. Then, the glyphosate is organized as a mycelium around ZnO NCs at neutral pH. Also, as the pH varies from acidic to alkaline, new crystal structures occur, which goes from star-like to volcano-like shapes. For an efficient quantification of glyphosate using ZnO NCs, it is essential to correlate the pH to its method. The acidic medium is recommended for optical methods, while the basic medium is more suitable for gravimetric methods, and neutral pH is ideal for spectroscopic analysis in FTIR and Raman. Therefore, in this study, we demonstrated that tuning pH could change the identification method to improve accuracy.

中文翻译：

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草甘膦：受 pH 变化控制的 ZnO 纳米晶相互作用

在受控 pH 条件下研究了除草剂草甘膦与氧化锌 (ZnO) 纳米晶体 (NC) 的相互作用。根据红外光谱，这些变化改变了草甘膦分子的各种化学基团的振动频率。扫描电子显微镜 (SEM) 和原子力显微镜 (AFM) 图像表明，由于草甘膦的质子化，pH 值的变化会促进特定的构象变化。然后，草甘膦在中性 pH 值下组织为围绕 ZnO NCs 的菌丝体。此外，随着 pH 值从酸性变为碱性，会出现新的晶体结构，从星状到火山状。为了使用 ZnO NCs 对草甘膦进行有效量化，必须将 pH 值与其方法相关联。光学方法推荐使用酸性介质，而碱性介质更适用于重量法，中性 pH 值是 FTIR 和拉曼光谱分析的理想选择。因此，在本研究中，我们证明了调整 pH 值可以改变识别方法以提高准确性。