Surface-enhanced Raman spectroscopy studies of organophosphorous model molecules and pesticides

Abstract

This work reports the analytical application of surface-enhanced Raman spectroscopy (SERS) in the trace analysis of organophosphorous pesticides (trichlorfon and glyphosate) and model organophosphorous compounds (dimethyl methylphosphonate and o-ethyl methylphosphonothioate) bearing different functional groups. SERS measurements were carried out using Ag nanocubes with an edge square dimension of ca. 100 nm as substrates. Density functional theory (DFT) with the B3LYP functional was used for the optimization of ground state geometries and simulation of Raman spectra of the organophosphorous compounds and their silver complexes. Adsorption geometries and marker bands were identified for each of the investigated compound. Results indicate the usefulness of SERS methodology for the sensitive analyses of organophosphorous compounds through the use of vibrational spectroscopy.

Highly sensitive SERS quantification of organophosphorous chemical warfare agents: A major step towards the real time sensing in the gas phase

“…The Raman spectral profile ( Figure S7) agrees to within a few wave numbers with previous reports [47,48]. The most intense signal appearing at 715 cm -1 , mainly assigned to the P-CH 3 stretching, has been used as Raman reference line.…”

SERS analyses of thiamethoxam assisted by Ag films and nanostructures produced by laser techniques

“…SERS has been used for trace analyses and detection of residue of different organophosphorous pesticides and insecticides by employing various NSs, such as a solution of 100 nm Ag nanocubes or a Klarite Au‐coated SERS‐active substrate . For instance, Liu et al reported a detection of dimethoate at concentrations of 0.5 to 10 μg ml −1 acquired by confocal Raman microspectrometry with Klarite substrate.…”

“…Concentrations of R6G as low as 1 nm have been measured, and a maximum enhancement higher than 10 5 has been achieved using Au-coated ZnO nanorods. [3] SERS has been used for trace analyses and detection of residue of different organophosphorous pesticides and insecticides [17][18][19][20][21][22] by employing various NSs, such as a solution of 100 nm Ag nanocubes [18] or a Klarite Au-coated SERS-active substrate. [19][20][21] For instance, Liu et al [19] reported a detection of dimethoate at concentrations of 0.5 to 10 μg ml −1 acquired by confocal Raman microspectrometry with Klarite substrate.…”

SERS-Based Sensitive Detection of Organophosphorus Nerve Agents

“…The Raman spectra of sarin and MPA were simulated based on density functional theory (DFT) by means of the Gaussian 09 software [44]. Figure 8(a) is the measured Raman spectrum for the pure MPA.…”