Rapid Surface-Enhanced Raman Spectroscopy Detection of Chlorothalonil in Standard Solution and Orange Peels with Pretreatment of Ultraviolet Irradiation

Abstract

At present, the detection of chlorothalonil is generally based on chromatography and immunoassay; both of which are time-consuming and costly. In this study, Surface-enhanced Raman Spectroscopy (SERS) has been successfully utilized in the detection of chlorothalonil coupled with photochemistry and meanwhile, gold nanoparticles were prepared to enhance the Raman signal. Two Raman peaks (2246 cm − 1 and 2140 cm − 1 ) of chlorothalonil were appeared after ultraviolet (UV) irradiation compared to the original solution. Chlorothalonil generated excited and weakened C≡N bonds in its structure by absorbing UV energy, thus leading to two kinds of corresponding peaks. These two kinds of peaks were both selected as analytical peaks in chlorothalonil detection. Different light sources and solvents were made different contributions to the final spectra. Chlorothalonil methanol solution under 302 nm wavelength irradiation was performed the best. The 2246 cm − 1 sharp peak represented to the normal C≡N bond appeared at first, which overall trend was significantly increased followed by a gradual decrease. The 2140 cm − 1 broad peak represented to the weakened C≡N bond appeared later, which overall trend was increased as the irradiation time passing by and then kept stable. Natural bond orbital (NBO) analysis indicates that the downshift of C≡N bond from 2246 cm − 1 to 2140 cm − 1 is due to the increase of electronic populations of π* orbital of C≡N bond transited from π orbital excited by UV irradiation. The positively charged C≡N bond had more chance to approach negatively charged gold nanoparticles. The detection limit of chlorothalonil was as low as 0.1 ppm in the standard solution. Orange peels spiked with chlorothalonil oil were also detected in this paper to confirm the practical operability of this method. The SERS method may be further developed as a rapid detection of pesticides that contains a triple bond by utilizing photochemistry.

Innovative Application of SERS in Food Quality and Safety: A Brief Review of Recent Trends

“…Chemical contaminants (e.g., chemical fertilizers, pesticides, veterinary drugs, and hormones) are major food safety issues [ 17 ], and many studies have reported comprehensive strategies for chemical contaminant detection [ 18 , 19 ]. Generally, foods can be categorized as liquid, solid, or solid and liquid mixtures, contaminants, or poisons distributed on the surface of these food types and can be detected by SERS [ 20 ].…”

Applications of surface‐enhanced Raman spectroscopy in environmental detection

“…While the toxicity of most fungicides is generally low, prolonged exposure to these compounds may lead to adverse health effects such as neurological disruptions 126 . Several recent studies have utilized SERS to detect various fungicides, including tetramethylthiuram disulfide (THR), 39,53,61,70,79,127–161 carbendazim, 162–165 chlorothalonil, 166,167 MG, 168–173 TBZ (a fungicide and parasiticide) 20,79,153,155,173–178 and ferbam 20,178,179 . Among them, THR is the most studied due to its wide agricultural applications and strong binding with SERS nanosubstrates through the thiol group.…”

Determination of chlorothalonil levels through inhibitory effect on papain activity at protein-decorated liquid crystal interfaces

“…It is relatively stable in the environment and adheres well to plants, resulting in significant amounts of chemical residue in the soil, water, and plants. Thus, CHL poses a significant threat to the environment and human health [ 3 ]. Furthermore, CHL was found to exert a carcinogenic effect on rat kidneys and a mutagenic effect on their offspring [ 4 ].…”