Study On Residue And Environmental Behavior Of The Acaricide Cyflumeotfen

Cyflumetofen,2-methoxyethyl(RS)-2-(4-tert-butylphenyl)-2-cyano-3-oxo-3-(α,α,α-trifluoro-o-toll) propionate, was developed by Otsuka AgriTechno Co.,Ltd. in2007. Cyflumetofen was arelatively novel acaricide active against spider mites and phytophagous mites at all developmentstages suiTab.for use in integrated pest management (IPM) systems without cross-resistance toexisting acaricides. Meanwhile, cyflumetofen was safe to predatory phytoseiidae mites as well asother non-target organisms, it was used for the control of a wide range of pets in fruits, ornamentals,vegetables, and other crops in Japan, and the use of cyflumetofen has increased dramatically inrecent years. However, the cyflumetofen may affect a lipid metabolism pathway although theunderlying mechanism(s) will need further studies for clarification. In addition, there is no limit forcyflumetofen residue levels in agricultural products in China. In this research, we established theresidue analysis method of cyflumetofen and conducted to study the hydrolysis, soil degradationand water-sediment degradation of cyflumetofen.The main findings are as follows:1、A new, highly sensitive and selective method was developed for the determination of thecyflumetofen residue in water, soil and fruits by using gas chromatography quadruple massspectrometry. The target compound was extracted using acetonitrile and then cleaned up usingdispersive solid-phase extraction with primary and secondary amine and graphitized carbon black,and optionally by a freezing-out clean-up step. The matrix-matched standards gave satisfactoryrecoveries and relative standard deviation values in different matrices at three fortified levels(0.05，0.5and1.0mg/kg). The overall average recoveries for this method in water, soil, and allfruits matrix at three fortified levels ranged from76.2%to101.5%with RSDs in the range of1.2-11.8%(n=5). The calculated limits of detection and quantification were typically below0.005and0.015μg/kg, which were much lower than the maximum residue levels established by JapanesePositive List. This study provides a theoretical basis for China to draw up MRL and analyticalmethod for cyflumetofen acaricide in different fruits.2、A rapid and effective method for the simultaneous determination of cyflumetofen and itsmain metabolite residues in samples was developed using ultrahigh performance liquidchromatography-tandem mass spectrometry (UPLC-MS/MS). Samples were extracted withacetonitrile and cleaned-up with multi-walled carbon nanotubes (MWCNTs). The determination ofthe presence of target compounds was achieved in less than4.0min using an electrospray ionisation source in the positive mode (ESI+) for cyflumetofen and B-3and the negative mode(ESI) for B-1. Average recoveries of the analytes were in the range of79.3-117.6%with relativestandard deviation values below7.6%. Limits of quantification (LOQs) ranged from0.7-9.8μg/kg，which were lower than the maximum residue limits (MRLs) for the cyflumetofen found in foods inJapan.3、Hydrolysis of cyflumetofen in buffer solutions at different pH values and temperatures wasexamined in the present study. It showed that the hydrolysis of cyflumetofen in different aqueousmedia follows first-order kinetics, with half-lives ranged from0.9h to23.3days. Comparisonbetween ground water and Milli-Q water suggested the contribution of biodegradation component.These results indicate that pH was used as a major parameter to predict the hydrolysis ofcyflumetofen, other parameter such as metal content and water quality probably showed effect onthe hydrolysis rate, but the effect was not significant such as temperatures.4、The degradation dynamic of cyflumetofen in soils followed the first-order kinetics. Thedegradation rate of cyflumetofen in the four soils was Sierozem>fluvo aquic>paddy fieldsoil>krasnozem, with the corresponding half-lives10.3d,11.2d,11.4d, and12.4d in the aerobic;and10.8d,12.8d,13.1d, and13.9d in the anaerobic, respectively. Soil microorganism and pHwas influenced for the degradation of cyflumetofen in soils. In the above four environments, thehalf-life for degration of cyflumetofen in4different kind soils for trial are both less than30d.According to the standard set by guidelines on environmental safety assessment for chemicalpesticides, cyflumetofen is belonged to easily degradable pesticide in soil.5、The degradation dynamic of cyflumetofen in the water-sediment system followed thefirst-order kinetics. In aerobic condition, the degradation half-life of cyflumetofen in the West Lakewater-sediment system, Hunan Paddy field water-sediment system, and Beijing Reservoirwater-sediment system are15.4d、16.9d, and15.1d. While in anaerobic condition, they are16.5d、17.3d, and16.1d, respectively. The degradation rate of cyflumetofen in the Beijing Reservoirwater-sediment system is higher than it in the Northeast Lake is higher than it in Hunan Paddy fieldwater-sediment system, and that in the water-sediment system in anaerobic condition is inferior toin aerobic condition. Mcrobial degradation to total degradation ratio is greater in the West Lakewater-sediment system than that in the Canal water-sediment system, and it is less in aerobiccondition than that in anaerobic condition of the two water-sediment systems. Hydrolysis to totaldegradation ratio is small in the water-sediment system and it is mainly Mcrobial degradation.