Study On Analysis Methods Of Nicotine Pesticide Residues In Edible Flowers From Yunnan

Objective:Yunnan edible flowers had a long history and good prospects for development.However,the problem of pesticide residues in edible flowers has attracted more and more attention.To establish the effective detection methods was the key to ensure the food safety of edible flowers.The edible flowers(Rose Rugosa,Chrysanthemum morifolium,Cerasus serrulata)from Yunnan was selected as the object of study,and the sample pretreatment and instrument testing conditions were optimized.Three methods including HPLC and MEKC were developed to test four pesticides(Imidacloprid,Acetamiprid,Hydrochlorothiazide and Cefotaxime)in edible flowers.Methods:Single factor test and orthogonal test were adopted,and sample pretreatment and chromatographic detection conditions of three methods were optimized.The RSD,recovery rate,detection limit and quantitative limit were evaluated,and finally the methods were applied to the detection of real samples.1.QuEChERS-HPLC:The HPLC conditions,sample extraction solvent,species and dosage of adsorbent(PSA,GCB,C18)were optimized;2.ASE-SPE-HPLC:the quantity of the sample,ASE time and temperature,SPE column and elution type were optimized;3.QuEChERS-MEKC:The concentration of borate,SDS concentration,pH,buffer system,capillary,separation voltage,injection time and so on were optimized.Results:1.QuEChERS-HPLCWith acetonitrile as the extraction solvent,PSA,GCB,C18 and anhydrous MgSO4 were added 65mg,15mg,25mg and 125mg respectively to clearn the solvent,the 4 pesticides had a good linear relationship in a certain concentration range(r>0.9990).The detection limit was in the range of 0.17?4.03?g/kg,the average recovery was 80.4%-105.6%,and RSD was 1.61%-6.33%.2.ASE-SPE-HPLCIn the temperature of 70?,the sample(3g)was extracted with acetonitrile for 5min using accelerated solvent extraction,then purification with C18 PC/NH2-SPE column,detected by HPLC.The pesticides had a good linear relationship in certain concentration range(r>0.9990).The detection limit was in the range of 0.49?g/kg?1.50 ?g/kg.The average recovery rate for edible rose rugosa samples rate was in the range of 89.30%?105.34%,RSD in the range of 0.34%?5.86%;the average recovery for edible chrysanthemum samples rate was in the range of 93.74%?106.91%,RSD was in the range of 0.19%?3.11%.3.QuEChERS-MEKCThe samples were extracted by acetonitrile and purfied by adding PSA 65mg,GCB 15mg,C18 25mg and anhydrous MgSO4 125mg.Using pH8.0 borate-SDS(10%volume methanol)as buffer solution,the separation voltage was 25kV,the injection time was 5s,the column temperature was 25? and the detection wavelength was 268nm.The 4 pesticides had good linear relationship(r>0.9980).The detection limit was 3.17?g/kg-6.33?g/kg,the average recovery for edible rose rugosa samples rate was the range,of 88.75%?103.94%,RSD in the range of 1.30%-4.72%;the average recovery for edible chrysanthemum samples rate in the range of 81.56%?101.82%,RSD was in the range of 0.70%?7.10%.The average recovery rate of edible cerasus serrulata as sample substrate is 92.43%-101.14%,and RSD was 0.82%?6.12%.The three methods mentioned above were applied to the detection of real samples,and no residues of nicotine pesticides were found in the samples.Conclusion:The method can meet the requirements for the detection of pesticide residues,and has good application value in agricultural product quality safety monitoring and risk assessment survey.