Characteristics of prepared fenpropathrin nano-emulsion and research on glutathione S-transferase enzymatic activity and penetration performance on T. cinnabarinus

Abstract

In this study, fenpropathrin nano-emulsion (NE) was prepared by phase inversion emulsification method. 8% xylene and 2% solvent oil 150 (The main component is 1,2,4,5-Tetramethylbenzene) were used as solvent, styrylphenolpolyoxyethylene and calcium dodecylbenzenesulfonate were used as surfactants. The particle size, zeta potential, conductivity and contact angle were detected to evaluate the characteristic of the nano-emulsion. Toxicity of fenpropathrin nano-emulsion on the pest mite, Tetranychus cinnabarinus, was analyzed. The particle sizes of 8% fenpropathrin nano-emulsion and 20% fenpropathrin emulsion concentrates (EC) were 31.53 nm and 459.00 nm, zeta potentials were –22 mV and 5.762 mV, respectively, which showed that the size of nanoemulsion was much smaller and its stability was higher than that of EC. The contact angles of these two formulations were tested in concentrations of 500 mg/L to 2000 mg/L. We found that the contact angle of NE at the same concentration was 32% lower than that of EC averagely. The results indicated that the wettability and adhesion ability of nano-emulsion droplets were better than those of EC on the biological targets. According to determination of penetration performance to T. cinnabarinus, it was found that the penetration performance of NE to T. cinnabarinus is 4–6 times higher than that of EC. With the characteristics above, the NE has exhibited higher biological activity on the T. cinnabarinus. The results of Glutathione-S-transferase (GSTs) enzymatic activity of T. cinnabarinus showed nano-emulsion had higher effects than EC. In conclusion, compared with EC, nano-emulsion has better penetration, biological activity and a great application prospect in pesticide field in the future.