Nuclear magnetic resonance chiral discrimination of fipronil and malathion agrochemicals: A case study

The aim of the present study was to optimize a protocol for nuclear magnetic resonance (NMR) chiral discrimination to be used to determine the enantiomers ratio of agrochemicals. For this goal, the commercial agrochemicals fipronil and malathion were employed as active targets due the distinct physicochemical properties. We used the cyclodextrins to evaluate the chiral discrimination in aqueous media and chiral solvent agents to check in organic media. The fipronil chiral discrimination was accessed by beta-CD in aqueous solution, although this procedure was ineffective for malathion due the low solubility. In organic media, the NMR chiral discrimination was successful for both agrochemicals and sensitive to dilution process. The NMR experiments explore very sensitive nuclei, for instance H-1, F-19, and P-31, in a simple, practical and low residue experimental protocol.