Study On The Residues Of Cyhalofop-butyl And Its Metabolites In Rice Field

A liquid chromatography for brown rice,rice husk,straw,field water and soil.The digestion rules of 10 % cyanofluoride emulsion and the final residue on rice were studied as a basis for the safe use and evaluation of cyanofluoride and metabolites ACID and DIACID in rice.The residual test of 10 % cyanofluororide emulsion in rice was completed,the residual level on rice was evaluated,suggestions for use were proposed,and the dietary risk assessment was conducted based on this residual amount result.The detection system of cyanoforide and its metabolites cyanofluoric acid and cyanofluoric acid in brown rice,rice husk and straw based on GC-mass spectrometry was established.The results show that the recovery rate of cyanofluoride in brown rice,rice husk and straw is 74 %～109 %,in brown rice,rice husk and straw 82 %～104 %,in brown rice,rice husk and straw 99 %～108 %.The quantification limit of cyanofluororide,cyanofluoric acid and cyanofluoric acid in brown rice,rice husk and straw was 0.02 mg / kg,and the retention time on the instrument was lower than10.0min,and the sample test results met the requirements of residue test criteria.After inspection,the detection method has fast peak output speed and good sensitivity,which is suitable for the rapid detection of multiple matrix type agricultural residue samples and large batch of agricultural residue samples.The stability results of cyanofurate and its metabolites in the 0-to 30% and17.6% in the storage days of-20 ℃,indicating that the stability of cyanoflothane and its metabolites cyanofluoroxalate and acid is good in the matrix of rice and rice field environment.This may be related to the acid and alkaline matrix of rice and paddy fields,maintaining cyanofluoride and its metabolites in the matrix samples,-20 ℃frozen storage conditions also inhibit the microbial activity in the matrix and weaken the digestion of cyanofluoride lines in the sample.Based on the test results,the test samples of cyanoforide and its metabolites and secondary acid in rice and rice fields were determined within the 180-day storage period,and the results should be accurate and reliable.The final residue test determined the content of cyanoforate and acetic acid in rice samples,and the results showed that the molecular content of cyanfluororic acid and basic acid were converted into the total content of cyanoforide in the rice samples did not exceed the maximum residue limit stipulated in GB 2763-2021: 0.1 mg / kg of brown rice.Based on the final residual test results,suggestions are given: 10 %cyanofluoride emulsion is used to control annual grass weeds,and the dose is180～225 g / ha of active ingredient,after 2 leaves and 1 heart,2-3 leaf grass weeds,water stem and leaf spray,at most once.Rice harvest during harvest.The test has proved that the application method is safe and feasible,and can be harvested in rice harvest and meets the maximum residue limit of cyanoforide.Combined with the median and maximum residual values on the brown rice matrix in the test,the dietary risk assessment showed that the risk entropy(RQ)was far less than 1.According to the recommended dose and harvest time of the field test,the potential dietary risk of its intake on brown rice is acceptable and safe.