Method for determining silthiofam residues in fruits and vegetables by GC-EI-MS (gas chromatography-mass spectrometry with electron impact ionization)

Abstract

The invention discloses a method for determining silthiofam residues in fruits and vegetables by GC-EI-MS (gas chromatography-mass spectrometry with electron impact ionization). The method includes: extracting residual silthiofam from a sample homogeneously by acetonitrile or an acetonitrile solution containing 1% of acetic acid, subjecting an extraction solution to matrix dispersed purification of ethylenediamine-N-propoxysilane (PSA) and an octadecylsilane bonded phase (C18) prior to GC-EI-MS detection, establishing a corrected standard working curve by a blankmatrix solution containing no to-be-detected pesticide, and quantifying by an external standard method. The method for determining the silthiofam residues in the fruits and vegetables by GC-EI-MS has the advantages that average recovery rate ranges from 82.9% to 87.1%, average RSD (relative standard deviation) ranges from 5.3% to 7.5%, detection limit is lower than 3.03 microgrammes / kg, and the method is simple and convenient to operate, rapid, high in sensitivity, good in repeatability, accurate in qualitative and quantitative determination and capable of meeting the technical requirements of countries such as America, European Union and Japan on corresponding product safety detection so as to provide a powerful technical support for people's food safety in China and healthy development of export trade.

Description

technical field [0001] The invention relates to a GC-EI-MS method for determining the residue of silthiocarb in fruits and vegetables, more specifically, it uses gas chromatography-electron bombardment ion source-mass spectrometry (GC-EI-MS) to qualitatively and quantitatively determine the residues in vegetables and fruits. The invention relates to a method for residual silthiocarb content, which belongs to the technical field of determination of pesticide residues. Background technique [0002] Silthiofam (common name: Silthiofam, test code: Mon65500, trade name: Latitude, other names: Silthiopham) is an amide fungicide developed by Monsanto. It is mainly used as seed treatment to control take-all disease on grains. Chemical name: N-allyl-4,5-dimethyl-2-(trimethylsilyl)thiophene-3-carboxamide, English name: N-allyl-4,5-dimethyl-2-(trimethylsilyl )thiophene-3-carboxamide, CAS accession number: 175217-20-6, chemical structural formula is: [0003] [0004] Appearance i...

AI Technical Summary

Problems solved by technology

[0007] At this stage, there are few studies on the determination methods of silthiocarb residues, and the detection methods reported are mainly the detection methods of silthiocarb residues in vegetables and fruits. These detection methods all use liquid chromatography tandem mass spectrometry (LC-MS / MS) is a detection method for the determination of silthiocarb residues in vegetables and fruits. Using LC-MS / MS to determine pesticide residues in food and agricultural products has the advantages of rapidity, simplicity, and high sensitivity. However, due to its high price, many testing institutions and enterprises Or the scientific research institute has not configured this instrument or the number of equipment is small. Since different compounds are detected by LC-MS / MS, different mobile phases or chromatographic columns need to be used, which requires constant replacement of chromatographic columns and mobile phases and takes a long time. The time to balance the system restricts the application of LC-MS / MS to some extent

Gas chromatography-mass spectrometry (GC-EI-MS) equipped with electron bombardment ionization source has great advantages in analyzing pesticide residues in food and agricultural products. Since electron bombardment ionization source mass spectrometry is a universal detector, it can realize multi-residue analysis of hundreds of pesticides. It can be qualitative and quantitative at the same time, and the price is moderate. Therefore, various testing institutions and enterprises are equipped with gas chromatography-electron bombardment ion source-mass spectrometer (GC-EI-MS) to detect pesticide residues in food and agricultural products, but so far no See the report on the GC-EI-MS detection method of silthiocarb residues in food and agricultural products, and the establishment of gas chromatography-electron bombardment ion source-mass spectrometry (GC-EI-MS) for qualitative and quantitative analysis of grains and animal-derived foods. The detection method of silthiocarb residues is of great significance

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