Rapid Analysis Of Pesticide Multiresidues In Vegetables And Software Development

In this paper,a new chemometric analysis algorithm was developed to realize the automatic qualitative and quantitative detection of multi-pesticide residues in vegetable samples.A standard mass spectral library of 237 pesticides was established,and a new chemometric method was developed for the automatic detection of pesticide residues in vegetable samples.Leeks,convolvulus,leek flowers,and yellowish leek samples can be rapid detected pesticide residues by this method.In addition,the standard mass spectrometry library and chemometrics algorithm of pesticide residues were softwarefied.The main research contents and results are as follows:(1)Establishment of pesticide standard mass spectrometry library.Gas chromatography-mass spectrometry(GC-MS)data of 237 pesticide were collected,and the data were standardized mass spectrometry data.At the same time,a pesticide standard mass spectrometry library was created and the pesticide residue mass spectrometry library search software was developed.(2)An improved moving window target transfer factor analysis(IMWTTFA)algorithm was proposed,which was verified by GC-MS data of standard elution and rapid elution of mixed pesticide standard methods.The results show that:multi-pesticide residues data were detcted by IMWTTFA,and and the detection results obtained by the rapid elution condition are consistent with those obtained by the standard elution condition.The method provides a new way for the rapid automated detection of multi-pesticide residues.(3)The mass spectrometry library and the new chemometrics method were used to rapid detected the pesticide residues in leek,convolvulus,leek flower and yellowish leek.The standard method of the Ministry of Agriculture was adopted to resolve the GC-MS data of the samples by the new chemometrics method established,that unknown pesticide residues in the sample to qualitative detected,and the method was further verified by the spiked experiment.In order to achieve rapid qualitative analysis of unknown pesticide residues in vegetables samples,the results obtained by the dipping method were compared with those obtained by the standard method.The results show that Captafol was detected in leek samples by standard method and dipping method combined with new chemometrics algorithm.Captafol and dieldrin were detected in convolvulus sample through standard method,however,no pesticides in them after analysis of dipping method.Captafol has detected after analysis of the leek flower standard method,while the different iprobenfos and dicyandiamide by the dipping method;no pesticide was detected by either the yellowish leek standard method or the dipping method.By comparing the qualitative results of the standard method and the dipping method,it is found that rapid qualitative analysis of pesticide residues in vegetables sample can be achieved by dipping method,however there may be a problem of detecting fewer pesticides,the reason may be that some pesticides are exist in the interior of vegetables rather than on the surface(4)By using the established mass spectrometry library and the new chemometrics method,the spiked samples of two different pre-processing methods were used for rapid qualitative and quantitative analysis of pesticide residues,and the standard curve of pesticide residue detection was established by using the standard addition method.The results show that the R~2of standard curve obtained by the standard method of leek flower without chemometrics analysis is 0.9715,and through chemometric analysis is 0.9985;the R~2of standard curve obtained by the dipping method of leek flower without chemometrics analysis is 0.7748,and through chemometric analysis is 0.9451.It can be concluded that the chromatographic signal obtained by chemometric analysis is more realistic and the qualitative results is more accurate by stoichiometric analysis.(5)In order to realize the automatic detection of pesticide residues in vegetables,combined with the mass spectrometry library of pesticide residues software,the matching software of pesticide residues mass spectrometry library and the analytical software of pesticide residues gas chromatography-mass spectrometry signal were developed.