An analytical method combining off-line flow-through extraction of a soil micro-sample (mass around 100 mg, packed into a short HPLC glass column) and direct on-column large-volume injection (LVI up to 1.00 mL) of a methanol-water soil extract onto a conventional C18 RP HPLC column enabled fast (within 3.5 minutes) trace micro-analysis of the relatively new chiral pesticides epoxiconazole (E) and novaluron (N), respectively. Linear calibration curves were evaluated from UV detection (230 nm) data in the range from 0.1 to 5 mg/kg in three most abundant Slovak agricultural soils. LOD (confidence band) at the levels 0.08-0.11 mg/kg and LOQ 0.4-0.6 mg/kg and LOD (S/N = 3) at the levels 0.007-0.018 mg/kg and LOQ (S/N = 10) 0.024-0.060 mg/kg, respectively, of dry soil were achieved. Recovery of pesticides in the overall LVI method including flow-through 130-200 mg soil micro-sample extraction was: for epoxiconazole from 74 to 85% and from 56% to 90% for novaluron with reproducibility within +/- 6% RSD. This fast (30 min) and simple method consists of just three steps which are short column filling with a solid micro-sample; flow-through liquid extraction and direct large-volume injection RP HPLC DAD analysis. The method is prepared for automation and further analysis of enantiomers of both investigated pesticides by achiral-chiral column switching techniques.
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http://dx.doi.org/10.1002/jssc.200700180 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
State Key Laboratory of Green Pesticide, Central China Normal University, Wuhan 430079, PR China. Electronic address:
The construction of helical structures through self-assembly and the exploration of their formation mechanisms not only amplify chiroptical properties but also provide profound insights into the structures and functions of natural helices. In this study, we developed a chiral Au(I) system based on BINAP and alkynyl ligands. The modification of the length or number of alkyl chains at the terminal positions of the alkynyl ligands significantly impacted the self-assembly behavior of the complexes.
View Article and Find Full Text PDFChirality
January 2025
Department of Pesticide Science, College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, China.
Chiral pesticides often undergo enantioselective degradation during food fermentation. In this study, the enantioselective fates of seven chiral pesticides during processing of wine and rice wine were investigated. The results revealed that R-metalaxyl, R-mefentrifluconazole and S-hexaconazole were preferentially degraded during wine processing with EF values of 0.
View Article and Find Full Text PDFOrg Lett
January 2025
Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
This work describes a chiral bifunctional squaramide/DBU sequential catalytic strategy for the enantioselective synthesis of nonfused chiral eight-membered O-heterocycles through the asymmetric addition of ynones to β,γ-unsaturated α-ketoesters followed by the regio- and diastereoselective cyclization of the adduct intermediates. Mechanistic experiments revealed that an isomerization process should be involved in the ring formation step, and the origin of the high regioselectivity and diastereoselectivity has also been elucidated by the DFT calculations.
View Article and Find Full Text PDFPest Manag Sci
January 2025
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China.
Background: Indoxacarb, a type of chiral pesticide, is used to control Lepidoptera insects. Most studies had focused on the environmental behavior and selective toxicity of indoxacarb enantiomers, and the mechanism behind its selective biological activity against target organisms is not well understood.
Results: Spodoptera frugiperda was selected as the target insect.
J Hazard Mater
January 2025
Honeybee Research Institute, Jiangxi Agricultural University, Nanchang 330045, China; Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Nanchang 330045, China. Electronic address:
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