The large use of herbicides applied in the control of agricultural pests has become a serious environmental problem. One of the concerns is the long persistence of these contaminants in soil and wastewater leading to the need of developing detection and quantification techniques. In this work, we applied surface-enhanced Raman scattering to detect prometryn herbicide using silver nanoparticles at low concentrations (ppb - parts per billion). The adsorption of prometryn on metallic surfaces was studied at different pH in order to optimize the interaction mechanism with the metal. The effect of pH is especially strong on prometryn, since it undergoes a chemical change at pH < 5 consisting in an hydroxylation of the triazine ring that leads to the hydroxylated prometryn. Thus, the quantitative analysis of prometryn was done at neutral and alkaline pH, at which prometryn interacts with the metal surface through the formation of coordination charge-transfer bonds. The detection of prometryn led to limit of detection of 1.2 × 10^-7 mol/L (28 ppb) at pH 11 and 5.3 × 10^-7 mol/L (128 ppb) at pH 7. The limit of detection at pH 11 is comparable to the concentration allowed to PRM in potable water by regulating organizations.

在控制农业害虫中大量使用除草剂已成为严重的环境问题。关注的问题之一是这些污染物在土壤和废水中的持久存在，导致需要开发检测和定量技术。在这项工作中，我们使用低浓度（ppb-十亿分之几）的银纳米颗粒，应用了表面增强拉曼散射技术来检测脯氨酰胺除草剂。为了优化与金属的相互作用机理，研究了在不同pH条件下脯氨酰胺在金属表面的吸附。pH值对脯氨酰胺的作用特别强，因为它在pH <5时会发生化学变化，该变化包括三嗪环的羟基化，从而导致羟基脯氨酸的羟基化。因此，脯氨酰胺的定量分析是在中性和碱性pH值下进行的，在该pH下，脯氨酰胺通过形成配位电荷转移键与金属表面相互作用。脯氨酸的检测导致检测限为1.2×10pH值为11时为^-7 mol / L（28 ppb），pH值为7时为5.3×10 ^-7 mol / L（128 ppb）。pH值为11时的检出限可与调节机构对饮用水中PRM的允许浓度相媲美。 。