Study On The Degradation Of Flucarbazone-sodium During Wheat Growth And Flour Products Processing

Flucarbazone-sodium is a novel sulfonylurea systemic herbicide with certain control effects on gramineous,cruciferous and broadleaf weeds.Excessive use or non-standard use of flucarbazone-sodium will remain in wheat plants,grains and soil,causing harm to humans and the environment.In order to understand the residual conditions in wheat plants,grains and soil after the use of flucarbazone-sodium and the effect of flour processing on the residues of flucarbazone-sodium,the detection method of flucarbazone-sodium and the degradation of flucarbazone-sodium in wheat growth and flour processing were studied in this paper.The content and conclusions are as follows:1.A rapid method for detection of flucarbazone-sodium in wheat plants,grains and soil by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry was established.The optimum conditions were optimized by single factor experiment:extraction with acetonitrile for 30min,100 mg GCB+100 mg MgSO₄ was used as a purifying agent,and 50%methanol water was used as the medium of liquid to be tested.The ESI-mode was used to detect flucarbazone-sodium.Flucarbazone-sodium was linear in the range of 0.1 mg/L¹ mg/L.The correlation coefficient（r）was greater than 0.995,and the minimum detection limit of the flucarbazone-sodium method was 0.005 mg/kg.The recoveries of flucarbazone-sodium at the spiked levels of 0.005,0.01,and0.5mg/kg were 79.6%to112.6%,and the relative standard deviations（n=5）were 0.85%to 4.63%,.The method has high extraction efficiency,good purification effect,simple operation,rapidity,sensitivity and low cost,and can simultaneously meet the detection requirements of flucarbazone-sodium in wheat plants,grains and soil.2.Through the two-year（2013,2014）three fields（Shandong,Anhui,Henan）experiment,the degradation of flucarbazone-sodium during wheat growth was studied.The experimental results showed that the half-life of flucarbazone-sodium in wheat plants was 3.33⁴.85 days,and the half-life of flucarbazone-sodium in soil was 15.40²3.90 days.Flucarbazone-sodium was a readily degradable pesticide.Spraying 45⁶7.5 g a.i./ha flucarbazone-sodium before wheat jointing,the content of f flucarbazone-sodium in wheat plants,grain and soil was less than the minimum detection limit of 0.005mg/kg.It was indicated that the flucarbazone-sodium can be completely degraded during the wheat growth under the method of use.Suggestions for reasonable use can be given as follows:5%flucarbazone-sodium dispersible oil suspension to control annual weeds,the highest dosage was 60mL/mu（active ingredient 45 g a.i./ha）,and the maximum application time was 1 time.3.By adding flucarbazone-sodium standard to non-polluted wheat flour,studied the degradatio n of flucarbazone-sodium during the processing of bread,steamed bread and noodles in different aspects（dough making,fermentation,proofing,pressing,cutting,baking,steaming,boilin-g）.The results sho wed that during the processing of flour,the five processes of dough making,fermentation,proofing,pressing and cutting had little effect on flucarbazone-sodium,explained that mechanical force and yeast fermentation had no effect on the degradation of flucarbazone.The degradation of flucarbaz one-sodium in the bread skin during high temperature baking（220℃,20 min）was significant,ind icating that high temperature can promote the degradation of flucarbazone-sodium;while steaming and cooking（100℃,20 min）,flucarbazone-sodium was not degraded,indicating that the flucarbaz one was stable under relatively mild processing conditions.Through the detection of flucarbazone-sodium in the noodles and noodle soup during the boiling process,the flucarbazone-sodium was t ransferred from the noodle portion to the noodle soup during the boiling process,but the total am ount did not change,It was further proved that 100 degrees Celsius did not have the conditions f or degradation of flucarbazone-sodium.The effect of additives on flucarbazone-sodium was investi gated by adding different additives during the processing of bread and noodles.The results show ed that ascorbic acid L-cysteine L-glutathione and sodium carbonate had no effect on the degrad ation of flucarbazone-sodium.