The Establishment Of Mass Spectrometry Database Include Interpretation Based On Pesticide Residue Analysis

In recent years, atmospheric pressure ionization, precise tandem, qualitative orquantitative analyses of pesticide residues by mass spectrometry are developing ac-tively and rapidly. The pesticides are different from the general organic matters, ac-cording to its chemical structures category, it is necessary to study and utilize in depth.Existing pesticide mass spectrometry data provide rich information but uncontrivedinformation is still need to launch KDD study. Learn from previous experience, we canreduce reliance on the mass spectrometry database capacity and the number of stand-ard ownership. And analysis workers of pesticide residues should become a qualifiedmass spectrometry expert. Pesticide residues analysis is related to legitimate trade offood and consumers‘safety, and in order to avoid to produce false-positive andfalse-negative results effectively, gradually lay foundation for the transition from tar-get test‘to screening test‘, therefore, it is necessary to carry out the establishment ofmass spectrometry database include interpretation based on pesticide residue analysis.On the basis of mastery of organic mass spectroscopy knowledge and mass spec-trogram of pesticides, focus on the MRLs provision of Codex, analyze and sum up,investigate the mass spectrogram rules, and select the qualitative and quantitativefragment ions. The main mass spectrogram of pesticides are collected on the internet,and we have self-tests to supplement the database. The EI of trans fluthrin and cyphe-nothrin are tested by GC-MS, and then digitized mass spectrograms of TXT are gener-ated. The information of pesticides mass was made public by internet, and it is on thebasis of JCAMP-DX format, edited TXT text file, according to JAVA script, digitalmass spectrogram were drawn. The web page is dynamic, it belongs to B/S architec-ture, and the tool used is SQL Server.The fragmentation rules of various types of mass spectrometry are as follows:The EI of organochlorine have apparent isotopic ion clusters, and accompanied byor proceeded by expulsion of Cl or HCl. The fragmentations of M35or M36areevident. It can be used as the judgment of compounds containing Cl. At the same time,on the electron bombardment, bridged polycyclic chlorinated hydrocarbons are typi-cally characterized by retro Diels-Alder （RDA） reactions （e.g. dieldrin, endrin, hepta- chlor etc.）.The general formula of N-methylcarbamates insecticides is（?）, on thecharge induction of oxygen atoms, the-breaking of amide group was easily happened,with characteristic fragmentations m/z58（CH₃NHCO+） and R+or R+H produced.Sulfur-containing oxime compounds have always m/z86（C3H4NO2+）, it is characteris-tic fragment ion.The pyrethroid insecticides were easily-broken in ester bonds and benzyl, andthe main characteristic fragment ions are m/z208, m/z181and m/z123that containingthree-membered ring. At the same time, observed series of benzene ions: m/z91, m/z77, m/z65, m/z51, and m/z39.The mass spectrometry database include interpretation based on pesticide residueanalysis was established and published on the Internet, and203pesticides‘mass spec-tra were interpreted. It‘s achieved the transformation of research results and resourcesharing. The database has a variety of ways to search, and is convenient to use. It pro-vides professional and technical guidance on the identification, screening and confir-mation of certain pesticides mass spectrometry. It is suitable for real-time rapid analy-sis and judgment in the laboratory. The database also provides some related infor-mation, including656kinds of pesticides mass spectrum that are generated from TXTtext file,2515kinds of pesticides‘basic information, some spectrum information ofpart of pesticides.