The Study Of Optimization And Application Of Analytical Methods Of Pesticide Residues In Chrysanthemum Indicum

ObjectiveTo establish a quick,easy,cheap,effective,rugged,safe,sensitivity and applicational methods by gas chromatography-mass spectrometry(GC-MS)for simultaneous determination of 37 pesticides in Chrysanthemum indicum.Optimizing of pretreatment method of analytical methods of pesticide residues in Chrysanthemum indicum,contamination condition of different sources were evaluated.Furthermore,matrix enhancement effect of chrysanthemum indicum was improved by Analyte protectants.Methods and resultsThe pretreatment of multi-residuces such as the parameters of GC-MS have been optimized.The experiments were performed on a DB-1701 capillary column(30mx0.25mmx0.25 μm)with a temperature programming which is initial temperature 50℃ for 1 minute,then heating to160℃ by the rate of 30℃/min,then to 200℃ by 4℃/min,then to 230℃ by 3℃/min for 2 minute,then to 250℃ by 2℃/min,then to 270℃ by 20℃/min,finally to 300℃ by 5℃ for 5mins.The inlet temperature was 230℃,column flow 1.3mL/min,splitless injection with 1 μL.The Ionization mode was El source with electron energy at70eV,transmission line temperature at 250℃,ion source temperature at 230℃,quadruple temperature at 150℃.Data acquisition mode was selected ion monitoring mode.MSPD pretreatment method:Aliquots of 0.5g sample and 400mg PSA/NH,(1:1,v/v)to the agate mortar,grinding the sample for 2 min and then transferred to a blank tube,then added anhydrous sodium sulfate about 2g on the top the tube.Eluting with 15mL solvent of hexanes/acetone(4/6,v/v).then concentration and resolve with hexanes to 1mL.QuEChERS pretreatment method:A representative 10 g sample was weighed in a 50mL PTFE centrifuge tube with 10mL of acetonitrile(with 0.1%glacial acetic acid),then shake the tube for lmin,added together with the mixture purchased from chemical company,and immediately the tube was vigorously shaken for lmin,The extract was then centrifuged(5000 rpm)for 5min.All of the supernatant were pipetted and transferred to a 15mL graduated centrifuge tube containing the mixture purchased from chemical company.Then,it was shaken for lmin.After that,the extract was centrifuged again(5000 rpm)for 5 min.To improve the Matrix effect of Chrysanthemum indicum,5 Analyte protectants was study,such as D-sorbitol,ethylene glycol,D-(+)-ribonic gamma-lactone,methyl-β-D-xylopyranoside,2,3-butanediol.The results show that 2,3-butanediol with the concentration is 1.Omg/mL is the best one.Contamination condition of Chrysanthemum indicum from different sources were evaluated by using GCMS-QuEChERS.The results showed that 63.16%of the 37 pesticides were detected.The detection rateo f Phorate,Profenofos and Aldrin&Dieldrin was 62.96%,59.26%,74.07%,but all pesticide residues were lower than standards except two batch samples with Aldrin&Dieldrin exceed standard.conclusionIn summary,these studies offer a new strategy to establish a gas chromatography-mass spectrometry(GC-MS)method for simultaneous determination of 37 pesticides.Compared with MSPD and QuEChERS pretreatment protocols.MSPD method was more complex opration than QuEChERS method.In our study,the matrix,induced response enhancement existed in MSPD and QuEChERS method.The pretreatment method of analysis of protectant of QuEChERS method was studied,and preliminary study results show that the concentration of 1.0 mg/mL of 2,3-butanediol can reduce the enhanced effect of matrix.But after the protectants added analysis,there exists interference such as certain interference peak and the response of individual peak or peak deformation is poor.The phenomenon need to be researched in the future and to fine the better analysis of protective agent.Considering the timeliness,this study selects the QuEChERS method for the study.Overall,our results showed that chrysanthemum indicum pollution is commonly existed phenomenon,but the residue is still relatively safe.