| The processing of agricultural products has a significant impact on the content and nature of pesticide residues,and the application of processing factors to carry out dietary exposure risk assessment of agricultural pesticide residues has become a research hotspot.After harvesting,Chinese medicinal materials need to be processed and processed by decoction and other decoctions before they can be taken into the human body.Processing factors have been used to study the effects of processing on pesticide residues in Chinese medicinal materials.In this paper,the Chaenomelis fructus of the same source of medicine and food is selected as the object,and the multi-residue analysis method of 6 common fungicides in C.fructus is established.Taking prochloraz and tebuconazole as representatives,the residue digestion dynamics and final residue tests of two fungicides on C.fructus were carried out.The research results provide a basis for formulating guidelines for the rational use of pesticides on C.fructus.1.Establishment of Multi-residue Analysis Method for Six Fungicides in C.fructus Fruits,Decoction Pieces and DecoctionsIn this paper,the Qu ECh ER method combined with LC-MS/MS was used to establish a multi-residue analysis method for six fungicides in C.fructus fruits,decoction pieces and decoction.The linearity of the method is good.LOD and LOQ are 0.69-2.10?g·kg-1 and2.29-7.01?g·kg-1,respectively.At 100,500 and 2000?g·kg-1addition levels,the average recovery of carbendazim,tebuconazole,difenoconazole,propiconazole,fluconazole and prochloraz in C.fructus fruits was at Between 77.78%-101.44%,RSD was 0.99%-9.30%.The average recovery rate of the added pieces on the pieces was 72.92%-105.14%,and the RSD was 2.82-10.24%.At the addition levels of 20,100,and 1000?g·kg-1,the average recovery rate of the six fungicides in the decoction was 79.72%-108.02%,and the RSD was2.32%-10.22%.The accuracy,precision and sensitivity of this analysis method meet the requirements of pesticide residue analysis,and can be used as a method for the detection of pesticide residues in C.fructus fruits?pieces and decoction.2.Effects of Different Processing Processes on the Residual Behavior of Six Fungicides in C.fructusThe residual behavior of six fungicides in C.fructus during processing showed that the degradation rates of carbendazim,tebuconazole,difenoconazole,propiconazole,fluconazole and prochloraz were respectively 91.84%,86.32%,79.87%,81.05%,89.45%and 84.26%.Processing factors were 0.0816,0.1368,0.2013,0.1781,0.0998 and 0.1574.The processing of C.fructus significantly affects the residual amount of six fungicides.Temperature and light are the important factors that affecting the pesticide residue behavior during the processing of C.fructus.3.Effects of decocing Process on Residues of Six Fungicides in C.fructusThe residual behavior of six fungicides in C.fructus during the decoction process showed that the removal rate of carbendazim,tebuconazole,difenoconazole,propiconazole,fluconazole and prochloraz in the decoction process They are 57.61%,84.58%,93.03%,84.08%,74.32%and 91.14%respectively.The decoction processing factors are 0.4239,0.1542,0.0697,0.1592,0.2568 and 0.0886,respectively.It can be seen that the decoction process of C.fructus.has a significant effect on the residual digestion of six fungicides.4.Digestion dynamics and final residual experiments of tebuconazole and prochloraz in C.fructus fieldsCombining processing factors and actual drug use,tebuconazole and prochloraz are used as representative pesticides for field trials.Study the dynamics of its digestion in the field during C.fructus planting.The results showed that the residual digestion dynamics of tebuconazole and prochloraz in C.fructus fruit conformed to the first-order kinetic equation,with half-lives of 2.94 d and 4.78 d,respectively,and after 14 days the digestion rates reached more than 96%.It shows that the two fungicides are easily digestible pesticides in the field.The final residue test results showed that:at a low dose?tebuconazole 75.0 g/ha and prochloraz 225.0 g/ha?,the residual concentration of tebuconazole and prochloraz in the sample was less than LOQ 10 days after the last application of the fruit.7.01 and 4.39?g·kg-1).At high doses?tebuconazole 150.0 g/ha and prochloraz 450.0 g/ha?,residues of tebuconazole and prochloraz in the fruit samples 10 days after the last application The concentration is less than LOQ.There is no maximum residue limit standard?MRL?for tebuconazole and prochloraz on C.fructus in China.Refer to the minimum MRL value of tebuconazole and prochloraz in fruits of the Ministry of Food and Drug Safety?MFDS?and the European Food Safety Authority?EFSA?at 0.05 mg·kg-1.The final residues on tebuconazole and prochloraz were significantly lower than the above MRL values 10 days after the last application at the above dosage. |
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