The indirect determination of the most used herbicide worldwide, glyphosate, was achieved by the SERS technique using hemin chloride as the reporter molecule. An incubation process between hemin and glyphosate solutions was required to obtain a reproducible Raman signal on SERS substrates consisting of silicon decorated with Ag nanoparticles (Si-AgNPs). At 780 nm of excitation wavelength, SERS spectra from hemin solutions do not show extra bands in the presence of glyphosate. However, the hemin bands increase in intensity as a function of glyphosate concentration. This allows the quantification of the herbicide using as marker band the signal associated with the ring breathing mode of pyridine at 745 cm⁻¹. The linear range was from 1 × 10⁻¹⁰ to 1 × 10⁻⁵ M and the limit of detection (LOD) was 9.59 × 10⁻¹² M. This methodology was successfully applied to the quantification of the herbicide in honey. From Raman experiments with and without silver nanoparticles, it was possible to state that the hemin is the species responsible for the absorption in the absence or the presence of the herbicide via vinyl groups. Likewise, when the glyphosate concentration increases, a subtle increase occurs in the planar orientation of the vinyl group at position 2 in the porphyrin ring of hemin over the silver surface, favoring the reduction of the molecule. The total Raman signal of the hemin-glyphosate incubated solutions includes a maximized electromagnetic contribution by the use of the appropriate laser excitation, and chemical contributions related to charge transfer between silver and hemin, and from resonance properties of Raman scattering of hemin. Incubation of the reporter molecule with the analyte before the conjugation with the SERS substrate has not been explored before and could be extrapolated to other reporter-analyte systems that depend on a binding equilibrium process.

使用氯化血红素作为报告分子的 SERS 技术间接测定了全球最常用的除草剂草甘膦。需要在氯高铁血红素和草甘膦溶液之间进行孵育过程，以便在由银纳米颗粒 (Si-AgNP) 装饰的硅组成的 SERS 基底上获得可重现的拉曼信号。在 780 nm 激发波长下，氯高铁血红素溶液的 SERS 光谱在草甘膦存在的情况下不会显示额外的谱带。然而，氯高铁血红素条带的强度随着草甘膦浓度的变化而增加。^{这允许使用与745cm -1}处吡啶环呼吸模式相关的信号作为标记带来定量除草剂。线性范围为1 × 10 ^-10至1 × 10 ^-5 M，检测限(LOD) 为9.59 × 10 ^-12 M。该方法已成功应用于蜂蜜中除草剂的定量。根据使用和不使用银纳米粒子的拉曼实验，可以指出，氯高铁血红素是在不存在或存在除草剂的情况下通过乙烯基负责吸收的物质。同样，当草甘膦浓度增加时，银表面上氯高铁血红素卟啉环2位乙烯基的平面取向会发生微妙的增加，有利于分子的还原。氯高铁血红素-草甘膦孵育溶液的总拉曼信号包括通过使用适当的激光激发而最大化的电磁贡献，以及与银和氯高铁血红素之间的电荷转移相关的化学贡献，以及来自氯高铁血红素拉曼散射的共振特性。在与 SERS 底物结合之前报告分子与分析物的孵育之前尚未被探索过，并且可以外推到依赖于结合平衡过程的其他报告分子-分析物系统。