Determination Of Fungicides In Fermented Food By Liquid-phase Microextraction Method

[Objective] To detect fungicides in fermented food,the dispersive liquid-liquid microextraction technology was used as the sample pretreatment method to extract,separate,and enrich the target substances in samples.Dispersive liquid-liquid microextraction is a new sample pretreatment technology,an efficient extraction method and concentration technology.It has the advantages of simple operation,rapid operation,and high enrichment coefficient.In this study,dispersive liquid-liquid microextraction technology combined with high performance liquid chromatography was used to establish a method for detecting pesticide residues in fermented,to achieve the purpose of environmental protection,new and efficient detection.The specific content includes the following three parts:[Method](1)In this study,a simple,efficient,and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent(ETA-ME-SDES)was developed to determine strobilurin fungicides in water,juice,wine,and vinegar samples by HPLC.A new and green deep eutectic solvent synthesized with thymol and octanoic acid was used as the extractant.The contact area between the extractant and the targets was increased by the method assisted by effervescent tablets to avoid the use of toxic dispersant.In this experiment,the type and the volume of extractant,and the amounts of ammonia hydroxide,sodium bicarbonate,citric acid and sodium chloride,the volume of sample solution,and pH values were optimized.(2)This research aims to simultaneously determine triazole fungicides in water,beer,Baijiu,and vinegar samples by HPLC.To achieve this purpose,this work develops a simple,fast,environmentally-friendly popping candy-assisted dispersive liquid-liquid microextraction technique.A green medium-chain fatty acid(decanoic acid)was used as an extractant and popping candy was used as a solid dispersant to avoid using toxic extractants and dispersants.Decanoic acid was collected after extraction by solidification at room temperature.In this experiment,the type of extractant,the volume of extractant,the amount of popping candy,temperature,the addition amount of sodium chloride,and pH were optimized.(3)A method for the determination of strobilurin fungicides and triazole fungicides in fermented food was developed by using cyclodextrin-assisted with organic solvent with dispersive liquid-liquid microextraction by high performance liquid chromatography.1-undecanol,a green and environmentally friendly organic solvent,was used as the extractant,which was separated from the sample through solidification.In this experiment,the type of extractant,the type of dispersant,the volume of extractant,the volume of dispersant,the amount of water added in cyclodextrin,the times of mixing,the amount of sodium chloride added,and pH were optimized.[Results](1)Determination of strobilurin fungicides in fermented food by effervescent tablet assisted and solidification with a low eutectic solvent with dispersive liquid-liquid microextraction by highperformance liquid chromatography.The limit of detection was 0.15-0.38 μg/L,and the recoveries were77.4-106.9%.The method has been successfully used to determine strobilurin fungicides in water,juice,wine,and vinegar.(2)Determination of triazole fungicides in fermented food by popping candy assisted and solidification organic solvent with dispersive liquid-liquid microextraction by high-performance liquid chromatography.The limit of detection was 8.1-11.2 μg/L.The extraction recovery was 80.8-102.5%.The method has been successfully applied to the enantioselectivity determination of triazole fungicides in water,beer,baijiu,and vinegar.(3)Determination of strobilurin fungicides and triazole fungicides in fermented foods by cyclodextrin-assisted and solidification organic solvent with dispersive liquid-liquid microextraction by high-performance liquid chromatography.The limit of detection was 0.3 μg/L.The extraction recovery was83.2-103.2%.This method has been successfully applied to the determination of strobilurin fungicides and triazole fungicides in water,juice,and vinegar.[Conclusion] This study based on the dispersive liquid-liquid microextraction technology combined with high-performance liquid chromatography method to establish the three kinds of detection of pesticide residue detection method in fermented foods,adopt green,environmental protection organic solvents as extractant,the effervescent tablets,popping candy auxiliary,auxiliary methods such as auxiliary extraction agent dispersed cyclodextrin,solidification methods will be solid-liquid separation,extractant and the sample of three methods,rapid,efficient,green is suitable for the detection of pesticide residue of fermented foods.