Vegetables In Pesticide Residue Detection Method In Leafy Vegetables In Pesticide Residue Monitoring, And Jinan

Objective:At present,pesticide residues of organophosphorus,carbaminate and pyrethroid insecticides are used most extensively in our country.Pesticide residues in vegetables entering human body will cause great damage of different system and function.In order to investigate situation of pesticide residues in vegetables in Jinan city,we have set up a GC-MS technique,which is simple and easy to apply in laboratory and suited to analyze samples of large number,meanwhile it can test dozens of common organophosphorus,carbaminate and pyrethroid insecticides, also we make a wide survey and analysis of situation of pesticide residues in vegetables in Jinan city.Methods:We have ameliorated the standard method,after extracting samples with acetone and dichlormethane mixed with the same proportion,purifying and concentrateing them with two solid phase extract methodes,then make a quantitative and qualitative analysis of samples with GC and GC-MS technology.This method is precisely quantitative and qualitative,and is a kind of dependable method for to do trace analysis.1.Dealing with samples:Cutting up,then comminuting and homogenizing the samples,weighing nicety 20g and transferring to triangle bottle,put into acetone 50ml,dichlormethane 50ml,and fair amount of anhydrous sodium sulfate according water content in vegetables,ultrasonic extracting,Solid Phase Extraction purifying, vaporizing until to dry on circumgyrating vaporization machine.Dissolve acetone and decide capacity tolml.2.Condition of GC analysis:American VARIAN Corporation CP-3800 gas phase chromatograph,with the Electron Capture Detector and the Nitrogen Phosphorus Detector;The nonpolar,weak polarity and medium polar capillary vessel chromatographic column.The split/splitless specimen handling,the chromatographic column temperature control were done according the temperature programs. 3.Controlling of method quality:The external standard method,draws up each kind of pesticides separately the specification curve,and progressive dilutes again the standard series's smallest density,the specimen handling analysis,obtains various pesticides to pick out limits.Takes two concentration standards,redundants them mensurate 5 times in one day,mensurate continuously for 3 days,obtains the precision in one day and the precision during the days.Takes the cabbage,the fragrant-flowered garlic and the carrot as representatives,does recovery experiment, and calculates the percent recovery and the precision.4.Range to samples:all of the 454 samples are from Lixia region,Huaiyin region and Licheng region of Jinan city,including big supermarket,wholesale market and Economic and Trade market。The period for collecting sample is from 2006 to 2007,including every month in 2006 and part of in 2007.all the samples of vegetables include leave category,bulb category,melon and fruit category,rhizome category and so on.5.Kinds of pesticide residues:we have tested 11 kinds of forbidden pesticide residues including Methamidophos,Phorate,Parathion-ethyL,Parathion-methyl,isofenphos-methy,Monocrotophos,Omethoate,Ethion,Isocarbophos,Metolcarb,Carbofuran and 20 kinds of limited used pesticide residues including Phoxim,Phosmet,Dichlorvos,Dimethoate,Acephate,Chlorpyrifos,Fenitrothion,Metrifonate,Malathion,Fenthion,Quinalphos,Cypermethrin,Permethrin,Permethrin,Fenvalerate,Cyfluthrin,Deltamethrin,Pirimicarb,Carbaryl,Methomyl etc.Conclusion:1.There are 20 organophosphorus pesticide,5 carbaminate and 6 pyrethroid insecticides seperated well on specifically chromatographic column,with nice standard curve,value r:0.9991～0.9999,the lowest testing content:0.005 mg/kg～0.025 mg/kg,the standard solution precision:RSD 4.0%～7.8%,the percent recovery: 70.9%-112.3%,recovery precision:RSD5.0%-12.6%.2.Influence to result of forward dealing with samples:thought recovery experiment and precision is quite same among liquid-liquid extraction,Rope extraction process and solid phase extraction.But using the ameliorated SPE,we could once extraction detecting three classes pesticides.It is easier operated,costs least reagent,suits to quick analysis of kinds of pesticide residues in vegetables。3.From 2006 to 2007,we tested 454 pieces of sample,the result showed that 9.7%of them fall short of national principle.Amongst these samples, disqualification rate of cabbage and green leaves is highest.Disqualification rate of leaves is marked higher than melon and fruit and rhizome.Disqualification rate of vegetables not in season is marked higher than fresh vegetables in season Disqualification rate of vegetables in summer and fall is marked higher than those in winter.Disqualification rate of those with "green" symbol is marked lower than common ones.The rate of toxicity pesticide is higher.