Soil contamination from organophosphorus pesticide production poses serious threats to human health. Understanding the degradation behavior of pesticides is crucial for developing effective remediation strategies. In this study, novel, highly effective extraction methods, including accelerated solvent extraction and online solid-phase extraction tailored for organophosphorus pesticides, were developed. Phorate and its degradation products were identified in a contaminated site of an organophosphorus pesticide factory in northern China using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Key metabolites detected included phorate sulfone, phorate sulfoxide, phoratoxon, phoratoxon sulfone, and phoratoxon sulfoxide, along with other degradation products identified via GC-MS's unknown compound identification and deconvolution functions, and further analyzed with Compound Discoverer software. Various degradation pathways that led to the final formation of diethyl disulfide, formaldehyde, and hydrogen sulfide from phorate were uncovered. Among them, a novel degradation pathway for the intermediate O,O-diethyl thiophosphate was identified, where O,O-diethyl thiophosphate generated O,O,O-triethyl phosphorothioate in the presence of ethanol. Furthermore, four pathways leading to the formation of a newly identified compound, triethyl thiophosphate, were established: (1) phorate undergoing intramolecular nucleophilic hydrolysis via a six-membered ring transition state to form O,O,S-triethyldithiophosphate, which was subsequently oxidized; (2) O,O-diethyl thiophosphate, generated through phorate hydrolysis, reacting with ethanol; (3) diethyl chlorothiophosphate reacting with ethyl thiol; and (4) diethyl chlorothiophosphate being oxidized to diethyl chlorophosphate. Collectively, these findings provide essential evidence for understanding the fate of phorate during the natural attenuation of contaminated soils.
ReS2, as a new member of transition metal dichalcogenides (TMDCs), has emerged as a promising substrate for semiconductor surface-enhanced Raman spectroscopy (SERS) due to its unique optoelectronic properties. Nevertheless, the sensitivity of the ReS2SERS substrate poses a significant challenge to its widespread application in trace detection. In this work, we present a reliable approach for constructing a novel ReS2/AuNPs SERS composite substrate, enabling ultrasensitive detection of trace amounts of organic pesticides. We demonstrate that the porous structures of ReS2nanoflowers can effectively confine the growth of AuNPs. By precisely controlling the size and distribution of AuNPs, numerous efficient and densely packed “hot spots” were created on the surface of ReS2nanoflowers. As a result of the synergistic enhancement of the chemical and electromagnetic mechanisms, the ReS2/AuNPs SERS substrate demonstrates high sensitivity, good reproducibility, and superior stability in detecting typical organic dyes such as rhodamine 6G and crystalline violet. The ReS2/AuNPs SERS substrate shows an ultralow detection limit of 10−10M and a linear detection of organic pesticide molecules within 10−6–10−10M, which is significantly lower than the EU Environmental Protection Agency regulation standards. The strategy of constructing ReS2/AuNPs composites would contribute to the development of highly sensitive and reliable SERS sensing platforms for food safety monitoring.Keywords:ReS2nanoflowers;ReS2/AuNPs complexes;surface-enhanced Raman spectroscopy;quantitative detection
危险品化学品经营许可证（带存储）