title: Enantiomeric discrimination and quantification of the chiral organophosphorus pesticide fenamiphos in aqueous samples by a novel and selective ³¹P nuclear magnetic resonance spectroscopic method using cyclodextrins as chiral selector.
abstract: A rapid, selective, and accurate quantitative ³¹P nuclear magnetic resonance (³¹P NMR) spectroscopy method was used for the chiral recognition of the racemic organophosphorus pesticide fenamiphos using chiral solvating agents (CSAs). Six neutral cyclodextrins (CDs) (α-CD, β-CD, methyl-β-CD, hydroxyethyl-β-CD, hydroxypropyl-β-CD, and hydroxypropyl-γ-CD) and two anionic CDs (carboxymethyl-β-CD and carboxyethyl-β-CD) were selected for these experiments. The shift displacement values (Δδ), after addition of each of the eight CDs in the highest possible molar ratio to a guest, were recorded. The results showed that β-CD and hydroxypropyl-β-CD were the best chiral solvating agents for the enantiomeric discrimination of fenamiphos. Two-dimension rotating frame nuclear Overhauser spectroscopy (ROESY) was used to investigate the structure of the β-CD-fenamiphos inclusion complex in aqueous solution. To determine the fenamiphos enantiomers, a calibration curve was drawn for two enantiomers over the range of 0.05-0.25 mg mL⁻¹. The limits of detection (S/N = 3) were obtained as 0.0068 and 0.0060 mg mL⁻¹ for fenamiphos enantiomers. The recovery studies were performed on aqueous real samples ranging from 94 to 107% with coefficients of variation of ≤ 9%.
authors.affiliation: Department of Chemistry, Faculty of Science, Alzahra University, Vanak, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Molaabasi
authors.forename: Zahra
authors.initials: Z
authors.lastname: Talebpour
mesh_terms: D003505:Cyclodextrins; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009943:Organophosphorus Compounds / Q000032:analysis* / Q000737:chemistry*; D015203:Reproducibility of Results; D012996:Solutions; D013237:Stereoisomerism; D014867:Water
chemical_list: D003505:Cyclodextrins; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds; D012996:Solutions; D014867:Water; C002698:fenamiphos