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Pesticide multi-residue testing is the ability to simultaneously determine multiple pesticides in one analysis
.
In order to meet the challenge of a large number of test samples, a variety of pesticide multi-residue methods have been developed at home and abroad that can determine hundreds of pesticides in vegetables, fruits or grains
Since the application of the Mills-Olney-Gaither (MOG) method in 1963, with the development of instruments and the development of new technologies, along with the emergence of new pesticide compounds, different detection methods have emerged in endlessly
.
The development of detection methods and the use of new technologies to improve methods should meet the following requirements: ① clarify the significance of residual confirmation; ② lower detection limit; ③ lower analysis cost; ④ shorter analysis time; ⑤ wider analysis range
A brief review of the development process of pesticide residue analysis methods can increase our inspectors' understanding of the meaning of pesticide residue detection and enhance the sense of mission
.
(1) The introduction of the first commercial gas chromatography instrument in 1955 and the advent of capillary gas chromatography columns in 1958 provided a hardware basis for pesticide residue detection
.
(2) In 1963, three scholars such as Mills reported for the first time a single pure acetonitrile extraction method for the detection of organochlorine pesticides and other non-polar pesticide residues in low-fat foods (MOG method).
This method became a subsequent method development Basic, but cannot detect polar organic nitrogen and organic phosphorus pesticides
.
(3) In 1971, Becker et al.
improved the method of Mills et al.
, using acetone instead of acetonitrile as the primary extractant to extract organochlorine, organophosphorus, and organonitrogen pesticides from food, and then used dichloromethane and petroleum ether as a compound solvent for the second extraction.
Extract water to remove water, and use a carbide for purification
.
(4) In 1975, petroleum ether replaced acetone in the separation step to eliminate some precipitates in fruit analysis
.
(5) In 1981, a flame photometric detector (FPD) appeared to detect phosphorus and sulfur, and a conductivity detector (ELCD) to detect halogen and sulfur
.
(6) In 1982, the chromatography column could complete the extraction and purification steps at the same time: mixing the sample solution with silica gel or alumina to remove grease
.
This method is more effective than liquid-liquid distribution extraction and Flori silica purification
(7) In 1983, Luke et al.
used acetone as an extractant, purified samples with Florisil, and used gas chromatography to detect the content of organochlorine and organophosphorus pesticides in low-water and low-fat foods
.
In this method, NaCl is added to the extract to saturate the water phase, increase the ratio of acetone in the organic phase, thereby greatly increasing the polarity of the organic phase, and greatly improving the recovery rate
(8) In 1985, solid phase extraction was produced, C 18 was attached to silica gel, and ion exchange resin (XAD) was used in the extraction and pretreatment of pesticides in gas and water samples
.
(9) From 1977 to 1987, the confirmation method of compound groups was further developed
.
C 18 purifies carbamate, benzyl urea, and benzimidazole pesticides, and then uses HPLC with different detection systems for detection
(10) From 1984 to 1988, double capillary gas chromatography was produced, including the use of columns of different polarities and multiple detectors, thus eliminating the need for thorough purification
.
(11) In 1993, the Carins method used solid phase extraction column for purification
.
The solid phase extraction method has two advantages: First, the application of C 18 removes non-polar compounds in the sample through a reverse phase purification
(12) The generation of mass spectrometry, high-sensitivity detection technology, combined with capillary gas and liquid chromatography for pesticide residue analysis, can more accurately qualitative compounds
.
(13) In 2003, a universal pesticide residue detection sample pretreatment technology that integrates extraction and purification-QuEChERS method was produced
.
Pay attention to matrix effect and compensation technology
(14) At present, new materials such as carbon nanotubes, bonded functional magnetic beads, and various faster and more efficient adsorption filtration purification methods are all used in the pretreatment of pesticide residues
.
In terms of instruments, the combination of chromatography and triple quadrupole mass spectrometry has been popularized, and the high-resolution mass spectrometry technology has begun to be applied to risk monitoring, risk assessment, and nutrient function component analysis
