The Effect Of Pesticide Adjuvants On The Amount Of Pesticides Deposited On Bananas

In this paper,the residue analysis method of difenoconazole,bifenthrin and propiconazole in banana leaves,whole fruit,pulp and soil was established by gas chromatography tandem mass spectrometry?GC?MS/MS?.At the same time,the effects of three kinds of spray auxiliaries added with mineral oil,organosilicone and fatty acid methyl ester ethoxylate sulfonate?FMES?on the deposition and degradation dynamics of the above three pesticides on banana were investigated.The food safety of banana fruit provides data support for the rational use of pesticides and auxiliaries in banana gardens.In the pretreatment process,the extractant was screened,and acetone and acetonitrile?V:V=1:1?were finally determined as extractants for banana leaves,whole fruit and pulp samples,sodium chloride salting out,anhydrous sodium sulfate to remove water.Using C₁₈ as a purifying agent,using GC?MS/MS for testing;soil samples were selected as acetonitrile as extractant,sodium chloride was salted out,anhydrous sodium sulfate was used to remove water,C₁₈ was used as a purifying agent,and GC?MS/MS was used to detection.Difenoconazole,bifenthrin and propiconazole linearly is good linearly in the range of 0.005?20?g/mL in banana leaves and soil,R²?0.9989;linearly is good linearly in the range of 0.005?2?g/mL in banana whole fruit and pulp,R2?0.9991.The limit of quantitation?LOQ?of difenoconazole,bifenthrin and propiconazole in banana leaves,whole fruit,pulp and soil matrix was 0.02 mg/kg.The spiked concentrations of difenoconazole,bifenthrin and propiconazole in banana leaves and soil were 0.02?20 mg/kg;the average recoveries were 73.11%?105.43%,76.27%?104.73%,76.80%?108.42%;relative standard deviation was 0.86%?8.20%.The spiked concentrations of difenoconazole,bifenthrin and propiconazole in banana whole fruit and pulp were 0.02?2 mg/kg;the average recoveries were 79.20%?100.95%,79.18%?98.12%,78.60%?108.99%;relative standard deviation was 2.34%?8.15%.In Hainan and Guangxi,it can be concluded that in the initial deposition of banana leaves for 2 h,the mineral oil treatment group was 1.30?2.13 times of conventional water treatment group;the organosilicon treatment group was 1.22?1.60 times of conventional water treatment group;The initial deposition of difenoconazole,bifenthrin and propiconazole was not well improved in the FMES treatment group.Compared with the water control group,organosilicone and mineral oil additives can increase the initial deposition of difenoconazole,bifenthrin and propiconazole pesticides in banana leaves,the residue of pesticides remained at a high level at 0?14d;the effect of FMES on increasing the deposition was not obvious.The half-life of degradation of this three pesticides in Hainan was 3.79?9.00 d,and the half-life of degradation of this three pesticides in Guangxi was 1.91?5.37 d.The half-life of degradation of this pesticides in Guangxi was significantly faster than that in Hainan.According to the analysis,the temperature,rainfall and light intensity in Hainan and Guangxi are not much different from those in Guangxi,but the wind speed in Guangxi is obviously larger than that in Hainan.Therefore,wind speed may be the main cause of the difference in half-life of degradation between the two places.In different application modes in Hainan and Guangxi,the mineral oil adjuvant treatment group could not increase the degradation half-life of difenoconazole,bifenthrin and propiconazole in bananas compared with the water control group.In most treatment groups,the adjuvants of FMES,silicone and cumulative experiment treatment groups increased the degradation half-life of difenoconazole,bifenthrin and propiconazole in banana leaves compared to the water control group.In the field application of the two fields,the residue of difenoconazole in bananas was<0.02?0.08 mg/kg on the 14th day after application;the residue of propiconazole in bananas was<0.02?0.13 mg/kg;the residue of bifenthrin in banana was<0.02 mg/kg.In China,the maximum residue limits for difenoconazole,bifenthrin and propiconazole in bananas are 1 mg/kg,0.1 mg/kg and 1 mg/kg.Therefore,harvesting bananas 14 days after the last application can allow the pesticides to degrade enough time to ensure food safety.The distribution of pesticide residues in different matrices was studied.In Hainan,in the single application of water the content of this three pesticides in banana leaves accounted for 36.12%?58.14%,and 25.00%?63.08%in soil,0.72%?12.21%in whole fruit,0.08%?4.65%in the pulp;the content of pesticides in different matrices exist:leaf?soil>whole fruit>pulp.In Guangxi,the content of this three pesticides in banana leaves accounted for 77.52%?93.26%,the content in the soil accounted for 2.25%?20.31%,and the content in the whole fruit accounted for 1.36%?2.25%,and the content in the pulp accounted for 0.40%?2.25%;the content of pesticides in different matrices exists:leaf>soil>whole fruit>pulp.There are many weeds in the banana garden in Guangxi,and there are many plants on the surface that the pesticides drifting into the soil are less than those in Hainan.In the two trials,the pesticide content in the leaves is the highest and the content in the pulp is the least.