Toxic Fluoride Phosphate Racemic And R (s) Enantiomer In Tobacco On The Absorption, Distribution And Transfer

Dufulin is a new aminophosphonate antiviral agent discorvered by our lab, and the registration of Dufulin has been approved with high bioactivity by Ministry of Agriculture of China. The concentrations and enantiomeric ratio (ER) of Dufulin racemates and the enantiomers were traced by high-performance liquid chromatography (HPLC) to analyze systemic behaviors including uptake, distribution and translocation at different time intervals after spraying. The fortified recovery tests of the three antiviral agents in Nicotiana tabacum were performed with HPLC after samples pretreatment process and experimental condition optimazing. It was found that the recoveries were found to be in the range of 84.5% to 97.2% with the relative standard deviations (RSD) of variation from 1.5% to 4.6% for Dufulin racemate. For R-enantiomer, the recoveries were found to be in the range of 85.0% to 95.1% with RSD of variation from 1.6% to 8.5%. While for S-enantiomer, the recoveries were found to be in the range of 85.6% to 91.6% with RSD of variation from 1.8% to 7.4%. The minimum amount of detection was 2×10^-8 g. The detectable limit of concentration was 0.10μg/g. This method can follow detect the concentrations of Dufulin racemates and its enantiomer.Dufulin racemate and R(S)-enantiomers were analyzed by qualitative and quantitative after method validation. The systemic behavior including uptake, distribution and translocation were built up to explain the processes. Dufulin racemate and R(S)-enantiomers were absorbed into plant tissues by systemic action, and then translocated into the whole plant tissues through stems. Dufulin racemate was kept in racemic form (ER=1:1) in plant tissues after treatment of the leaves. Moreover, after spraying the R(S)-enantiomer, the stereo structure of the enantiomer was retained in plant tissues via chiral HPLC analysis. The maximum uptake of Dufulin racemate and enantiomers were 145.5μg/g at 7 days after spraying. The concentrations of Dufulin racemate and enantiomers in different plant tissues following the order: treated leaves (65.2μg/g) > stems (16.9μg/g) > untreated leaves (11.4μg/g) > roots (3.68μg/g). Compared with the enantiomeric selectivity of systemic behavior, the R(S)-enantiomer is more quickly absorbed than the racemate, and rapidly transferred to other tissues. In brief, three agents exhibited different system behaviors, probably due to their different stereo structures.